I agree with you about the horrors of the Soviet Union, but if you want people to know what happened, why remove a bunch of highly accessible primary sources?
I agree with you that we should not remove "a bunch of highly accessible primary sources" .su is not that kind of source. .su "was assigned as the country code top-level domain" and that country does not exists. It is not like picture, book or building. Why should we use it now?
And that domain online just because of his owners greed