At a high level, I have no control over your actions, you have no control over mine. We can argue until we're blue in the face, but when someone walks away after that argument, they're free to do as they please.
Physically, you don't need to eat meat. I'd recommend a good dietician if you want to go vegetarian or vegan, at least until you figure enough out that you can maintain the intake of all your required vitamins and nutrients as you transition. There are more than a few of them that are typically provided by meat products for most people's eating habits, you'll want advice on how to suppliment that without relying on pills. Suppliment pills can be helpful, but you probably don't want to have to take them all the time.
Eating meat can certainly be healthy too, speaking mainly for ones nutritional needs. The nutrients in meat are, in some cases, fairly rare in plants, so it can vastly simplify the job of meeting your nutritional needs.
For vegans, on a social and societal level, I agree with the concepts surrounding factory farming and the unethical treatment of the animals that become meat. No argument from me. However, thinking that any meat consumption is tantamount to murder, is not a view I share. Animals, and their meat, are eaten by other animals (including humans - separate from farming... I'm talking about actual hunting here). In nature, there's no hesitation about this, no remorse, and no known sorrow from the animals who "lost someone" to being food. Sadness over the passing of an individual is almost (but not entirely) a human phenomenon. Same with morals and ethics... To name a few. Ethically, I don't personally have a problem with animals dying for food. I do however have a problem with the abuse and maltreatment of animals that will become food. While alive, animals should be given some measure of dignity and respect. They should not be forced into living their lives in small cages and jammed together with hundreds of their kin in a confined space the way factory farming often does.
Eating meat does not and should not imply that a person is complicit nor agrees with the concept of factory farms or anything they do. Some people do not have the time, effort, money or focus to dedicate to finding alternatives. You don't know their life and you should not judge based on their eating habits alone. It's presumptive and arrogant to think that people have the bandwidth to even grok the concept of changing their entire lifestyle because of factory farms. In the same manner, vegans and vegetarians should not be negatively judged for their decisions either.
The only points of contention I have in the whole debate is that eating meat, in and of itself, whether you bought it off a shelf or obtained it through hunting, does not make one a murderer; and, while it's fine to share ideas, demanding that others change their ways because you have an opinion, is unacceptable. If someone is curious and willing to listen, sure, chat all you want. However, telling them that their choices are wrong and that they must do something differently, isn't a practice I can support.
At the end of the day, as most people learned from the lion king, there's a circle of life. Things will die so other things can live. Plants will absorb the minerals and nutrients from the rotting corpses of so-called "higher" life forms, and those "higher" life forms will eat the plants to live. Those plant eaters will be eaten by other animals, who will eventually die and become fertilizer for the plants. The cycle continues. Eating animals is something that animals do all the time, and it's not condemned. News flash, humans are also animals. We have the ability to eat and gain strength from meat. You have the free choice to either partake in that activity or not, but make no mistake, that's your personal choice.
IMO, we should all eat more vegetables. Meats have become so prevalent that there's basically meat included in every meal of the day. That's a bit much. Eat a salad. Everyone should reduce their meat intake, at the very least. If you want to go all the way to being vegetarian or vegan, go for it. It's your choice, your life, your body, and you're free to use it, and/or abuse it, in whatever way you wish.
For me, the ethical problems of factory farms are definitely an issue. Personally, I'd rather see a regulatory solution for the treatment of animals, since it would improve the life of all of those animals (at least for the duration they're alive), and improve their situation when they are slaughtered, so it is more humane. After they have been slaughtered, my level of care about how they're treated, pretty much disappears. As long as the resultant product is safe and not harmful, I couldn't care less. I'm only concerned with their life from birth to death. After that, meh. Regulatory changes would be simple and more effective than trying to change the hearts and minds of everyone in an effort to have the pubic at large, stop eating meat; bluntly, trying to convince an entire society to do anything for it's own good, is pretty much impossible. I'm not sure what the "annoying vegans" (not all vegans, just the ones who get in people's faces about it), are trying to prove. They won't convince everyone, it's basically impossible. It's like they've taken on this impossible task and it's not going well, and they're steaming mad about it.... Bro, you did this to yourself. I believe the only way to put an end to the animal abuse in factory farms, is to regulate it. I don't know what that regulation looks like, I'm not a lawyer, nor do I have any ties to nor interest in becoming a politician/government decision making person. I know change is needed and I have no ability to enact that change, but I would vote for anyone who did.
I don't consider death, in and if itself to be inhumane. I consider torture to be inhumane. I consider forced imprisonment in a small space to be inhumane. I even consider suffering to death, it be inhumane. Euthanizing something, can absolutely be humane. I don't believe that factory farms are being humane by my standards.
I don't think that asking them to be humane to their flock is too much to ask. Our food deserves it. They're giving their life for your ongoing existence and enjoyment, the least we can and should do, is ensure they're not spending that life in pain.
I highly recommend you check out a book called "A Bold Return to Giving a Damn". It's about a cattle rancher who turned his ranch into a form of regenerate agriculture. One of his main point is that the current meat industry provides cheap meat that is subsidized by the environment. His ranch is called White Oak Pastures. Fascinating book and definitely changed the way I look at meat consumption. I still eat meat but my extended family raises a cow every year so I think its a little but better than the industrial food system currently at work.