That's pretty much exactly what is going on. I suspect they have some kind of very narrowly defined criterea where it can get kicked up to an actual human, but since everyone except bots wants their disputes viewed by a human they have to keep it narrow or else they'd be overwhelmed (or they could hire a proper content management department, but that would involve committing to spend money long-term).
I suspect they also don't really want to moderate content effectively, because as soon as they start showing they can they'll have to justify keeping all the bullshit artists, bigots and bots on the website.