What's with trolls who are thin-skinned? 🤔

Users who go around posting raunchy or incendiary pics obviously to troll and goof around, yet they'll also block you if you bother them enough. Which, from what I've seen, is never that hard to do. Seems a bit odd to me. Begs the question as to why they're even trolling people if they can dish it but they can't take it. If you're gonna be dumb you gotta be tough and when a troll can easily become the trolled, they're clearly out of their element.