At MathOverflow > Help center > Reputation & Moderation I see the following:
[...] a user who voted for one of your posts had their account deleted (either by request or due to violating the network's terms of service). As a result, all of their votes were removed, and the reputation you gained or lost from them was undone. The resultant reputation change could be any amount [emphasis mine -- I.P.]; it could even be a reputation gain if enough of the removed votes were downvotes.
So, a user's account was deleted for whatever reason, but another user (say X) loses points, even though X's questions or answers were found useful by the deleted user.
What could be the logic here?
I understand that there may be hopefully exceptional cases when the deleted user's voting activities involved fraud of some sort. But it appears that X loses points if a user's account was deleted for whatever reason, with the following exception:
[The text at the linked page also has this:] We have a system in place that examines the impact of removing a user's votes. If the user has cast a large number of votes, deletion will be held up so staff may consider preserving the votes prior to the deletion.
It is I guess better than nothing that there are effots to minimize the negative impact. But why cause any negative impact at all? Why not reduce the nullification of the votes only to cases of voting fraud?