I think (1) potentially has a place for cases where it’s supposed to be background music that you wouldn’t really pay attention to (but shouldn’t repeat).

It’s pretty easy to take a style of music and produce something that sort of goes round and round modulating into different keys and so forth without actually going anywhere in particular.

But what you’re really doing is composing a parameterised piece of music and the randomly substituting parameters as you play it. This is what people are doing in real-life with things like cocktail piano anyway. If you can’t compose to begin with then you don’t stand a chance, however.

"Uncanny" is quite subjective when it comes to music. I know of at least 'DeepBach', Feynman Liang et al.'s (2016) 'BachBot' and Daniel Johnson's (2015) 'biaxial-rnn' as algorithmic music systems that could all be described as 'quirky' in many ways, but definitely not 'off'. And they're not limited to 'simplistic' music styles - all of them deal with Western music of the common practice period, which is quite non-trivial. Their main limitation is modeling structure beyond the 'short musical phrase' level, but that's to be expected.

Those are all very clearly quirky enough to be considered "off" by people who understand Bach's music and the classical tradition more generally. And the large scale structure problem is one of the primary reasons the whole thing is so hard in the first place.

But my point is that 'quirky enough to be considered off' is a rather subjective and context-dependent POV. The main issue really is the lack of consistent structure beyond the very short term, but aside from that the music seems to replicate many interesting features of the style, and it's certainly interesting enough to be listenable. Clearly it doesn't sit within the classical tradition of composed music, but it really is quite passable as 'noodling' or improvisation.

Regarding 2a: human music that most people listen to (e.g. on Spotify) is also handpicked to show only the best results.