Flirted with stints of vegetarianism. Still eat far less meat than "average" and can go many days without meat.
I am okay eating animals, they are tasty. They think, they die, they go to my tummy. I try to eat grass fed and "humane" local stuff these days precisely to avoid issues that occur at mass produced meat factories (antibiotic needs, etc.). This makes meat cost more, which makes me eat less.
The central reason for me comes down to sustainability. Eggs and milk are still not the most humane things to me, but they are sustainable and quite a bit better than killing the animals they come from. They cost way less to produce and eggs/cheese/dairy make a lot of tasty stuff I am less willing to give up than meat.
We can probably sustain the planet if everyone eats a light to moderate amount of dairy/eggs, but based on what I have read we really can't do that with the amount of meat consumption in America (and other places that are meat heavy in their culture.)
Not only that but Americans are used to cheap meats and are very very slowly becoming used to paying for meat at prices where it can be raised more healthily (legitimate free range, zero antibiotics due to much lower animal density, etc.)
tl;dr save the planet, and maybe because I occasionally feel bad animals die for me to live a more convenient life.
edit: also, regarding the fish only "vegans"...honestly... it is hard enough to safely define one thinking meat from another. I think people do a lot of mental twists and turns and narrative building to convince themselves that something like say, fish, are "lesser" thinking meats. Insects? Fungi? Bacteria? How do you define your thinking meat? The philosophy of this is actually fiendishly difficult if you take it seriously and don't just stop when your brain has convinced you that you have it figured out. I also don't think it is even subjective, even though it is a very passionate subject. At some level if you eat animals you have to accept the consequence and can't just rationalize away you are eating the muscles and fats of an animal that had its own thing going on. I just never felt strongly convinced by the whole strict vegan argument given the amount of energy required to live that way (it is actually hard and difficult to be a really strict Vegan, in my opinion that time can be better spent reducing misery of actual humans in a lot of cases)