Why do Republicans bring up Kamala's "lies"/shortcomings as a way to claim Trump is better?

That's what they've done for like 8 years now, it's the foundation of Whataboutism. No matter what you pin on Trump, they'll jump on some other real or imagined wrong, no matter what it has to do with the conversation, and use that as justification for anything that Trump has done or will do. It's just a way to sidestep or confuse the issue.

• "Trump is literally talking about becoming a fascist dictator."
• "Yeah, but in the 12th century, Genghis Khan killed like 20–40 million people, that's what we're facing from Chi-na, they're going to slaughter everyone if we don't do anything about them and their takeover of China-store Kamala, she's bought and paid for!"
• "WTF is wrong with you?"

The purpose of your post is to "beg the question" and launder a false premise that "she lies" as if the Republicans had any meaningful claims to make in that area. They don't. Your core position here is flawed.

Yes, trump is worse on all accounts. Always. Put him next to just about any living human being, save for the ones who's pants he drools on, he's worse. Without anything close to an equivalence.

There are three practical reasons Trump does this:

1. Deflection: Trump doesn't have an affirmative platform. As a populist strongman, Trump's platform is situational and entirely based on what his supporters want to hear in any given moment. If health care is in the news, Trump will say his plan is coming in two weeks (it won't ever come). If immigration is in the news, Trump will say he will build a wall and get Mexico to pay for it (he won't). But what's even easier? Focusing on the shortcomings of the opponent's platform. Any time this works, Trump saves himself an opportunity to be put under the microscope.
2. Deflection: Manipulating the media works. Trump knows that the more ludicrous things he says about Kamala, even if the media then starts to talk about how he's wrong or fact-check him, the focus is still on the thing he said rather than Kamala's platform. It's subtle, but it really does focus the media effectively on whatever he says, and use his frame of that issue as the media's frame.
3. Filling the echo chambers and other spaces. We're in our own echo chambers like never before. Trump says these things so that the people in the right-wing echo chambers have a plausible response to Kamala's policies, or even just need filler for their broadcast/websites/Facebook groups. Ultimately there is only so much media people can consume every day. If Trump has filled all relevant supporter spaces with his own opinions & framing, there is no time or energy left to explore other opinions and framing.

Why are republicans making it sound like Trump hasn't lied even moreso than Kamala?

Because it works with their idiot base.

It's just what you do when your side doesn't have a justifiable platform on it's own merit: See: All the people who keep telling us to ignore all the bad stuff corporate dems do because Trump would be worse.

IF you could actually run on things people liked, you'd talk about that and perhaps only call out your opponent's opposition to the things you support or show how they might be lying about claims that they want similar things.

But when your core platform is "let rich people keep doing what they want," you have to find ways to deflect from that.

Just out of curiosity is there any reason, you’re aware of, that you went for “Trump and Kamala” as opposed to “Trump and Harris” when you wrote your post? I’ve got no clowns in this circus so it’s a genuine question.

I was sitting at the doctor's office and overheard an old man claim Harris was so stupid that she couldn't figure out how to use a vacuum.

It broke MY brain trying to wrap my head around that one.

Some people choose to belittle others to make themselves feel bigger rather than strive to be better.

Republican supporters eat, sleep, and breathe contradicting thought. It’s baked into their worldview (looking at you, Christians).

They know what's going on, they know what they're doing. They just don't care, they like Trump they just can't argue their case and don't care to.

Generally speaking, a politician considers their voter base to either be the stupidest motherfuckers on the whole planet, or the most gullible. More often than not, it's the former

Because it's nothing more than a popularity contest for them. This isn't the future of the country (or world) for them, it's junior prom.

Repubs have nothing but DARVO to work with when mudslinging.

You could have a list of Harris' lies.

No one could compile a list of Trump's lies. It'd be much more reasonable to compile a list of truths he's said.

I'm trying to summon my inner Ben Shapiro here. This isn't my opinion but my understanding of what he has said on the subject.

While Trump lies a lot, he's fundamentally a bullshitter, which is different. A liar knows the truth but chooses to deceive, whereas a bullshitter doesn’t care about truth in the same way. When Trump says something like, "We’re going to withdraw from NATO," he’s often expressing a sentiment or creating leverage rather than making a literal commitment. He treats politics like business deals, where you start with an extreme offer, then meet somewhere in the middle. He has argued that in the case of NATO, for example, this approach worked: other member states did increase their defense spending (though the war in Ukraine played a role too).

So, the point is that Trump’s statements should often be taken as rhetorical posturing - ways to push for certain outcomes - rather than literal promises. From a Republican perspective, his actions during his first term ultimately aligned with their goals, which explains their relative tolerance of his exaggerations. In contrast, they see Kamala Harris (and Biden) as engaging in misrepresentation that has led to policies Republicans find harmful, so there’s a greater focus on what they see as her inconsistency between words and actions.

Some words.

There will always be sombody to disagree.

A good example, you could full whole heartedly be a kind and genuine person. And lets say theoretically, there is a poor starving man. You have food and give it to the starving man knowing your intention is to help and to not have any social, poltical, economical gain.

There will be people that claim he is not poor, people that will claim you did it a poltical, or social stunt. Are you sexist? You chose to help a man and not a women?? People that will paint you as the devil himself because your giving away food that sombody else could have had. Maybe there was sombody starving more? How dare you give away that bread!! There are millions of people and there will always be sombody who drinks the cool-aid.

Damn or be damned Make your choice with your best intent and live with it. For you will never know if it was the right decision, the world is emencly complex. I hope this helps explain politics and social antics.

I have learn alot of this lesson being autistic and seeing how others interpret mine or others actions and the potential outcomes.

Because politics?

It's easier than coming up with policy proposals I guess. Trump needs something to talk about besides border, border, border.

To be honest, I do the same thing. I would vote for a dead person to avoid Trump's shortcomings.

guy a is bad > implies guy b is better. not good, but better

Perhaps the lies of a serious politician are more significant than the ramblings of an insane clown.

Bikȯz Reıſizm. Ð quıit paṙt z ðæt Ðı þıŋk pruvıŋ Kamala luız mınz C'z æktcuėlı woṙſ bikȯz if Ðı'ṙ ıqėl, ðen Trump z betṙ ſinſ H'z wuıt æ C'z ė PvK.

Why do democrats bring up trumps "lies"/shortcomings as a way to claim kamala is better?

This isnt unique to a particular political party they all do it they always have they always will.

It's the opposite everytime someone criticize Kamala, her defenders can't stop bringing trump in the picture

Both American political parties do this often. It's much easier to attack your opponent for their transgressions than it is to prove your own aptitude and it seems to be just as, if not more, convincing to the average person. I don't think this should be particularly shocking.