Why are some Vegans/Vegetarians so mean to Pescetarians?

I am a vegetarian. I dont eat any animal but I applaud you for doing this! Not eating meat (but still eating fish) is great because you are at least doing something for the planet/animals/your own health :) You just gotta roll with it, most of my family are mennonites and they look down upon my choice even try to argue and provoke me... but i just ignore it cause I know that my choice is awesome lol