I am happy for people to eat whatever they believe makes them healthy.
I get cross when those who share a particular food belief get all evangelical about it and try to convince me, often with arguments for which there is not a shred of validated scientific evidence, that they are right and I'm wrong.
If anyone is even vaguely interested I'm mostly a Mediterranean omnivore: meat makes up about 15% of our diet. But there are times when we don't eat meat for a week of so, and others where we eat meat every day.