I have this conversation at least 10 times per day as I am a certified plant based chef and new clients or people who learn I am a chef are curious. Obviously it's an individuals choice whether they eat meat or not but science and longevity shows minimizing animal protein consumption reduces the risk of many illnesses. The thing with food is, it's addictive and since animal protein, especially when cooked, can light up the senses, it's hard to not like it. I have heard all the arguments and watched YouTube videos and been on some panels and it is all the same, they say "you have to eat animal protein to gain muscle" or "we eat meat as cave men" that's the individuals choice but look up plant based bodybuilders of endurance athletes, also look at country's with the lowest obesity rates, mostly plant based (not vegan) very small amounts of animal protein, lots of veggies (fibrous carbs) and starches (simple and complex carbs)
I cook for a lot of clients which have amazing results, some completely plant based, some 70% but the introduction of lower animal based diet can only be a good thing, the nutrient density of animal protein is quite small compared to nearly any vegetable so the takeaway in my opinion is, if you feel you need animal protein, keep it to a minimum and load up on the veggies, you will feel a whole lot better.
I'm sorry but I think you're really overstating certain things.
-The idea that 'minimizing animal protei reduces the risk of many illnesses' does not actually have very solid scientific evidence to state it as such. It's certainly not as universally true as you claim here, and whatever 'evidence' exists relies largely on correlating factors and confounding variables. So for example a lot of the 'red meat is bad' results relies on 2 factors: research in the US being done in the US where people consume a lot of their red meat in combination with refined carbs (fries / hamburgers) and soda (hence why you get inexplicable results like 'red meat leads to diabetes'), and the almost universal tendency to group all processed meats into red meat category (so any effects you're seeing are largely from the nitrites, not from the meat itself).
Just about the only meat-related statement that's really properly supported is 'nitrites are bad'.
-Similarly, animal protein is a rather big category. Were you to split it up further... I have yet to see any research that actually finds any negative effects from poultry and fish (as long as it's not tainted / polluted). Any research producing a negative effect of meats tends to only do this for red meat (and usually for aforementioned reasons).
-The main driver of 'meat is bad for you' gospel is that it's a convenient way to cut people's meat production that suits many parties, whether it's environmental groups who found their cute animal videos weren't working, or governments who are looking to reach carbon goals. There's more 'wishful analysis' than actually strong data (and virtually no experimental data).
-Whether a switch from meat to something else is a positive development on people's health depends a lot on what you replace it with. What I'm seeing here is that many people replace meat with simply more processed meat-replacements and end up eating more carbs / grains. Whether that's actually an improvement for their health is highly doubtful, and at best we're running a large-scale health experiment (in the same way the fat-is-bad-propaganda led to a diabetes epidemic).
-While I do agree that being an athlete on a vegetarian diet is technically possible, it is definitly harder. Although this is anecdotal, in my climbing club you could consistently pick out the vegetarians based on their build; the meat eaters would build up significantly more muscle under similar training schedules.
-Obesity rates have very little to do with consuming meat. In fact people who switch to a carnivore diet (not that I'm a fan of it) almost invariably end up losing weight. If there's a correlation on a country level this is because the higher-meat-consumption correlates with 'western diet of processed food and too much sugar'.
Although I'm incredibly reluctant to draw too many conclusions from country-statistics (it's a minefield of statistical traps), it doesn't really support this statement either way.
-I do agree that eating more veggies and fiber is definitly a good recommendation - and likely far more important for people's health than reducing protein intake. Most research points at 'carbs and processed food' being the area where you should reduce intake, not the proteins.
Which is also why you find such remarkable similarities between people going on extreme diets, whether it's fully plantbased, carnivore or paleo; they all end up cutting out the processed junk and excess refined carbs.