I think this plays into it. We each carry personal baggage into the story. And maybe how much we hate a character relates to how much the qualities of that character overlap with the things that irk us most. I mean if someone was bullied, they might hate a character more if they matched up closely and reminded them of the real life bully.
I haven't seen the Wire yet. It's on my list, but the character you described is probably the type that would make me shout at the screen, "You f*cken idiot!" constantly.
