"Muh Human Nature" is a classic debunked liberal argument against socialism/communism. If you think you are 'left' then you really should maybe read some theory or watch some youtube videos or something. Second Thought has a lot of good intro to political economy explainer videos.
The larger point is that the workers that lack solidarity (as you claim), are specifically incentivized to think in this way by their boss under capitalism. "Crabs in a bucket" mentality is a good shorthand description of what I am talking about. The capitalists and bosses want workers to be in competition with each other, not in solidarity (think union organizing). This is why I called out your 'class traitor' thinking espoused by your comment. Brain worms refers to this. You have bad ideology in your brain due to living in the world of neoliberal capitalism, it has instructed you on how to understand the world. And you seem just fine with following those instructions to the letter.
I'm not arguing against socialism/communism, I'm arguing against the first paragraph in the meme you posted.
If you think you are 'left'
I don't.
The capitalists and bosses want workers to be in competition with each other, not in solidarity (think union organizing).
You have bad ideology in your brain due to living in the world of neoliberal capitalism, it has instructed you on how to understand the world.
This is faulty logic. The fact that an understanding of the world includes benefits to capitalists and bosses doesn't imply that the understanding of the world either (1) is incorrect or (2) came through their instruction. You've shown neither of those to be true.
I appreciate it is painful to acknowledge that bosses exploit workers and that one can find comfort imagining that the exploitation is due to factors which can be altered but wishing it to be so doesn't make it so.
the workers that lack solidarity (as you claim), are specifically incentivized to think in this way by their boss under capitalism
Their boss may well give them an incentive not to cooperate but that doesn't mean there aren't other, much more primal forces pushing towards the same end. Looking at the behaviour of workers and all humans for that matter, they don't seem to need any encouragement in order to step on each other.
"These days, at least in the West, there seems to be a consensus that capitalism is just "the way things are." Everyone from capitalist economists to your dentist to your weird uncle is firmly convinced that humans are just hard-wired for capitalism. Let's explore that idea. Hope you enjoy!"
If you're not able to express succinctly in prose whatever idea you think I need to waste my time watching be revealed in a YouTube video then I suspect it's not an idea worth paying attention to.