OoMango has requested to be unblocked (w:c:c:Thread:1498237). I figured I should let you know since you were active during part of the time that they were causing problems so you might have a better understanding of it. From skimming through their past activity, I am seeing tons of violations and I would probably recommend against an unblock if it came down to that.
As you say, there have been a rather substantial number of policy violations in the past, and I have yet to see any particular evidence that they have reformed their behaviour. As far as I recall, the last communication I had with them was when they expressed an intent to murder me around a year ago. As touching as it was to know they cared sufficiently to make such an interesting and as-yet unfulfilled threat, I have no particular reason to think that they would behave themselves. I would agree with your conclusion.