> "On a side note: I'm not vegetarian. I simply agree with those who are."
This was my position for a long time until finally making the jump at the beginning of the pandemic (vegetarian, will rarely eat fish sometimes).
For me, it was mostly about reducing suffering of other animals. I thought this way before but it's hard to change behavior and I liked hamburgers. I think this is the strongest argument and the environmental or nutritional arguments feel like side issues to avoid just tackling this issue directly. The meat substitutes are nice because they're close enough to satisfy the want at a cook out or something.
There's some long reasoning behind it, but basically 'thoughtful local eating of meat' or whatever just felt like a rationalization to me. If an alien came down to earth and loved eating humans, but said they thanked every human they killed and ate or that the humans had a decent 20yrs of life before they killed them (and they only ate local humans), it still wouldn't sit well with me.
In the above example I was basically the alien that understood and agreed with all the human arguments, but still ate human because I liked human burger. Being vegetarian makes my actions more consistent with what I think is the right thing to do.
In theory, you could draw some line at 'well humans and other more intelligent beings are different because they have dreams and a plan for their future'. Even if humans could draw this line perfectly (which I'm skeptical of), you'd still need to kill the 'lesser' animals in a way without suffering or fear. I just don't think that's logistically possible. It's definitely not the way it's done in practice anyway.