That should mean engagement. It serves up such bad videos that I disengage.
Once in a while I'll realize I just spent 20, 30 minutes looking at a streak of pretty decent stuff. Rare enough to be remarkable. Usually after just 3 or 4 consecutive crap clips I'll close it down and get back to work.
I doubt anything disengages a user faster than low-quality content. I bet it does it even faster than the authoritarian politics and bigotry YouTube seems to inexorable serve you.