Aye, there's the rub ;) How do you define "too similar"? If I invert the colors of Munch's The Scream, is that an original work? What if I pass it through a computer program I wrote to swirl it around in a spiral? I think those are clearly derivative works--you put the image in as input, put it through a mechanical transformation process, and get the same output for the given input. That description also applies to AI.
> these algorithms generate some general idea of the things it's trained on
Well, be careful here. AIs don't generate ideas. They take inputs, do some mechanical work on them, and output something derived from the inputs. There are no "ideas" involved here, it's a(n extremely complicated) mechanical transformation.
(To repeat myself, I don't know where I stand on the issue. I think there's good arguments on both sides.)