As a pescetarian, I consume a “vegetarian plus fish” diet. It’s easier to just say I don’t eat “air-breathing meat” (as most United States dioceses of the Roman Catholic church describe for fasting) or flesh from things that breathe, than to explain to people what a lacto-ovo-pesce vegetarian diet is.
A lot of people want to engage me in political debate when they learn this, assuming I’m a PETA member who espouses animal farming (overlooking the leather shoes, etc.). Vegans are offended that I’m not “pure”, and often scorn me as if I’m a detriment to their cause.
Really, it’s not a moral issue for me. I just happened to notice I had gone the first two weeks of Lent (in 1999 IIRC) without eating any meat but fish, so decided to continue the remaining two weeks as well. At the end, I felt better and had lost some unhealthy weight (I was rather sedentary at the time) so I never resumed eating meat or poultry.