I'm not in my 20s, I'll say that much. And I'm actually very well read and knowledgeable on nutrition, diet, biology, and medicine. I literally had a medical doctor ask me today if I worked in medicine because of the way I talked.
I was studying on two separate occasions to be a vet and a microbiologist (life had other plans).
I wholly disagree with veganism. I have no issues if someone wants to be vegan, but biologically humans do not work well with it. I do, however, think that most people (mainly in the west) eat too much meat. A normal diet should be around 10% to (max) 20% meats.
We simply cannot extract enough nutrition from a plant-only diet without going to extreme lengths (time, effort, and financial). And even then it doesn't always go well. There are hoards of ex-vegans that gave up because they were literally becoming malnourished despite their best efforts to learn and adapt.
I think it's fine if someone wants to (or needs to) be a vegetarian (pescatarian or lacto/ovo-vegatarian). My MIL got bitten by a lone-star tick when she was a kid, and she contacted that rare condition where the antibodies that the immune system creates to fight off a particular bacteria from the lone-star tick also binds to some proteins in red meat and poultry. She loves the taste of poultry and beef, but gets physically ill if she eats it. But she can eat fish or eggs just fine.
I also agree that the farming/cattle industry in the USA is, for the most part, abhorrent in their treatment of animals. And their extremely liberal use of antibiotics in raising cattle is creating all kinds of problems for us.
Fortunately, I don't live in the US, so the meat where I am is far higher quality with well treated animals. We also do not suffer the kinds of health problems the US does.
One thing that irritates me about vegans in general is how so many promote their way of life as being healthier. The old meme of "how do you know if someone is vegan? Don't worry, they'll tell you" is true. I've been told so many times by a person, completely unprompted and without context, that they're vegan (or newly vegan). They go on and on about getting so much better, and how everyone should be vegan, etc. What always fails to be recognized is that they feel better, not because of cutting out meats, but because they cut all the crap processed foods and all the sugars.
The very nature of someone becoming vegan is a lifestyle change, and with that comes a lot of hyper-focusing on what they are eating. And because eating vegan requires tracking and hitting all your macros with the goal of being healthy, it is natural that the process would also steer people away from junk food and processed foods in general.
That is where the health benefits come from with veganism. It's the removal of the well documented and well understood body damaging substances like high-fructose corn syrup.
As for your comment about cruelty. Like I said earlier, I do agree that many modern industrial farms are cruel, but that's an entirely different discussion than the merits of a healthy diet.
Now if you're going to say killing an animal for the purpose of eating it is cruel, then I don't know what to tell you. The vast majority of animals on this planet survive only by eating other animals. And the way they do it is definitely cruel and painful (and often gruesome and horrific).
Even our modern understanding of carnivorous vs herbivorous is changing. We're seeing more and more reports of "herbivores" eating other animals. Like deer eating birds (no, I'm very serious).
It's a simple reality and fact of biology on this planet; including us. Humans do not thrive on a plant-only diet. Meat simply is too nutrient and protein dense to do away with entirely. Should most people eat less meat? Absolutely. But zero meat is out of the question.
https://www.youtube.com/watch?v=MpxgzGnEF7E
And to be clear, I'm not trying to convince you to quit veganism. I'm just imploring you to be open minded that veganism isn't the answer for most people.