Disliking and discouraging vermin does not make me an animal killer, whitewave. Most people would not be happy with an infestation of rats or mice in their house. Or pigeons living on and damaging the fabric of their house. Feeding seagulls is almost certainly what made them lose their fear of humans in the first place - and anyway, they don't really need our help; they are pretty adept at stealing all the food they need, right out of people's hands!
My poor dear FiL, in his late 80s, became frightened to go out in his garden because the woman in the adjoining bungalow used to stupidly throw food up onto her roof for the herring gulls. They consequently nested there and would dive bomb him almost every time he went out. As he was nearly blind and had lost virtually all of his hearing, he had no warning and on several occasions they made him stumble. He was really very scared that he would have a fall with serious consequences. They are pests, pure and simple, and should not be encouraged. This was in Brixham and if you talk to any of the residents there they will tell you what an absolute curse these birds are.