I like to think of it as freeing them from the conversational prison that is Reddit. As such, I'm essentially doing them a favour. If I didn't find this so personally enjoyable, it would be a wholly selfless act.
My current approach to the Reddit game is reportmaxxing. I'll make innocent-sounding comments with subtle triggers that will enrage some people, then pretend I have no idea what they're talking about in their furious replies, politely winding them up this way in our back-and-forth until they say something rash that I can report them for.
If I can frustrate them enough to make a violent threat, that's usually enough to get their account permanently banned. And then I win.
I got an account with an 11-year history wiped out the other day, that's my high score so far. Good times.