Once again, you word the problem perfectly @meno, if this is indeed what's been going on. So, if I understand correctly, people are actually trying to game the UA algo to up their score? And they're doing so by unfollowing people who negatively affect said score? That's just horrible in the way you describe perfectly with that little thought-experiment.

Truly, that's what I admire most in this post: the little narrative allows understanding to come in a natural way. Let's hope these algo-gamers somehow get the moral of the story... :-)