Could someone please explain this *beep* ending?[Spoilers obviously]

Okay, clearly Daniel Clowes had a message to say but in terms of storytelling I have to say that after the first half of the movie the film actually started to irritate me. What irritated me mainly was the fact that Jerome see's the paintings of the murdered victims and not think "hey maybe, just maybe this guy is someone I shouldn't be around" I mean he seemed like he was at first but then he just went all *beep* up by trying to actually imitate the painting given to him.

What the *beep* was going on in his mind?! What was he thinking?! Was he seriously thinking that bringing paintings like that would give him recognition, and win him that special little prize thing?

I mean the fact that he spent time with Jimmy in the first place was already sketchy and I understood him going to Jimmy's when he has his heartbroken but after that it just becomes a mess. I loved the first half of the movie but what ended up happening with the strangler side plot kind of ruined it for me.