I can understand why that would upset you, it's not something I would have any interest in. I read the first chapter of Multiple Personality Detective Psycho and decided it was not to my liking in the least and dropped it. I didn't think the mangaka was a murderer or psychopath. I thought he was simply drawing what he wanted or what the editorial staff decided he should and moved on. So long as the artist isn't committing a crime I view it as a simple matter of choice. Either you like the story and read or you don't like the story and move on.
The artist is a pedophile y'all