Well if I take it as a serious point, I dont see still how its useful to bring it up. We can’t change our natural impulses, only how we react to them. Following a vegan diet is no more challenging physically or mentally than managing a regular diet if you have the same goals.
Its akin to saying that a mans nature makes it difficult not to sexually assault women. While technically true, it has nothing to do with identifying problems and creating solutions.
I’m struggling to find any good reason to bring up natural instinct besides as an excuse.
Quite a lot of people experience physical discomfort or pain from eating the things you listed.
A good portion of the world is lactose intolerant, justtpo point out an obvious one.
Meat can cause a “spike followed by a come down” effect somewhat similar to sugar in some people.
But what I think happens is that people dont make the connection between how they feel and their diet.