I usually block people on Tumblr because they call my angora bunnies lionheads (or tag them with kink or kin-related tags)... or because they said something homophobic about Poirot. Or, of course, because they're a bot or one of my Fandom Nemeses (these are all people who afaik don't know I exist whose names or styles are like fingernails on a blackboard for me).

But I had a friend who used to advocate blocking more liberally than you need to as a form of stress release and she would definitely say "Block them!!" every time I dropped "Wow, look at this dumb comment I saw on a community post!" in the chat. Maybe you ran into one of her school of thought.