Why was Quasimodo such a jerk?

Why make him the antagonist, of any of them? I meaaaan Quasimodo was just like a deaf, kinda slow-witted, non-jerk in the original story. Not a nasty jerk like this one. I just didn't really get it. Why not make him Igor or some unrelated monster or something. Or where they just going for the "French" thing so they could make him a French chef? So they're like, hey Quasimodo is French so let's do it. Lol?

I didn't get it. Out of all the "monster" characters portrayed, he was the least that was actually a villain...because, actually, he wasn't a villain or jerk at all. (Or even a monster.) Just a deformed gypsy orphan who lived up in a bell tower after being taken in by a priest. Meh