@Vlad Along those same lines, searching with the "Programming" facet seems to return a lot of user pages from Stack Overflow.
I don't have a multitude of data points for this, but here's one example. I tried intitle:-user and this returns no results — until I switch from "Programming" back to "All".
Perhaps something on your end could be tweaked to de-prioritize these types of results, as they aren't very information-rich for general searches.