Ohhh now that I've seen. I'm not really interested in the storyline of bendy so much that I'd want to...add an oc to it. I won't judge....
But it's and ink demon cartoon brought to life. How on earth is that supposed to be attractive?
But hey. People will do what they do regardless.
The same reason fanart is drawn for anything else I guess. Because they can, and because they can they will.
But in all honesty I haven't seen anything inappropriate drawn for bendy and the ink machine. I don't think it's that widespread.