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Today I noticed in my rep calculation a "-100 user was removed". I'm aware of the reason that votes on answers are rolled back if users who did the vote got removed. But that would account to only -10.
Now I have a single -100 line, which would either mean, that either
1. 10 users who all did vote on one of my answer got removed at the same time (very unlikely)
2. I guess it could be that the votes were on a anwer to a question of a particular user and got rolled back because the answer got rolled back
3. There's a bug somewhere the StackExchange
The case (2) is somewhat counterintuitive. It would mean that questions and their answers got removed, (just) because a user got removed. Even if the user did violate the StackExchange rules at some point, this would be yet no reason to legitimate the loss of knowledge.