I’ve never understood the reluctance to block or “unfriend” people who you were involved with or who cause you problems.
We built nderground so that people completely disappear on nderground when you break a link to them. Our motto is “On nderground you can’t find me”. This is a comment on privacy, but also on the fact that there is no search for people. You only see your friends and when you break a link to someone they can’t see what you write and you can’t see what they write (or post as photos).
This means that there’s no “nderground stalking”, as they is with Facebook. But we think that this is a feature, not a bug.