> However, I wasn't aware that distributors might not vet content prior to publishing.

Oh it's far worse than that. Some of them like the abovementioned LANDR also offer "AI-assisted music production", so there's that!

Very few do proper vetting. They'll remove your music in a heartbeat if someone reports you to them (even in cases where such a report is completely bogus), but they won't do much to vet you beforehand. If they did that, they'd be labels, not distributors. Their only job is to be the hoop you have to get through that you don't have on say SoundCloud or YouTube.