I’m pesci, have been since 1999. I am not completely opposed to eating meat as we are omnivores, but I have no desire to do so myself. I find meat is mostly not very nice (so much chewing?!?). When I gave up the limited meat I used to eat, I kept eating fish as frankly it’s easier, especially when eating out or abroad. It’s easier these days and there is occasionally more than one veggie choice on the menu. Back in the day eating out was really restrictive and various holidays were miserable (think constant omelettes in Paris).
Ideally I would eat no meat, fish or dairy. But I am pragmatic, a pp mentioned harm reduction which I am practicing, and the environmental aspect has become much more important to me over the years. Eating less is better than doing nothing. I also don’t care much about rennet or gelatine - I am quite in favour of ‘use the whole animal approaches’. And I wear leather shoes for a similar reason plus the fact that many vegan leather alternatives are made from plastic (although I think this is changing too).
pescatarian doesn’t necessarily mean a free for all on fish either. I won’t eat shark, swordfish, octopus, squid etc for conservation reasons (shark) and intelligence reasons (squid etc). I don’t each much tuna as it’s a bit problematic too, but will eat some tinned tuna on occasion. What I eat evolves as my understanding grows and tastes and options change.
I don’t feel guilty for eating a mussel or something, and a fish that’s lived wild feels okay to me to eat. I’d be comfortable eating an insect also.
What another pp said above also resonated they say they are vegetarian because they don’t like most meat. It definitely was part of my decision to give up all meat as people just don’t seem to understand that if you technically eat meat, you might not like all types/ want it all the time. It’s just more simple to give it all up and then I never get presented with a plate of lamb when I’m round someone’s house for dinner (boak).
people can be complex, they can have complex reasons and lots of distinct logical decisions underlying what they call to the outside vegetarianism or pescatarianism. And they make compromises, they are human.