one of my pescaterian friends would eat fish because she said that at least they get to swim around freely for part of their lives. I guess she was mostly opposed to factory farming and that's why she would not eat meat.
i wonder sometimes if people don't get confused because the macrobiotic diet is somewhat similar to the veg diet, but macrobiotics do eat some fish. i also wonder if it is because, in many people's minds, fish is not considered meat. in many restaurants, fish and meat are listed separately on the menu. it's usually not "pork" "beef" "lamb" all separate, but just "meat" and then "fish" is on a different page. "fowl" sometimes, too.
fish was the last meat i gave up. not because i liked it, which i don't, but because i needed time to get myself and the people around me used to my new diet. it is very, very difficult to avoid fish in japan. it is in all sorts of foods that look completely vegetarian on the surface. that reason probably wouldn't be the case in most western countries. but a lot of people think red meat is unhealthy, and, between fish and fowl, that fish is most healthy, so it is more socially accepted to refuse to eat red meat but continue to eat fish as one gets used to the vegetarian lifestyle.
"Somewhere along the way, someone is going to tell you, 'There is no "I" in team.' What you should tell them is, 'Maybe not. But there is an "I" in independence, individuality and integrity." Â George Carlin