Einstein died in, what, 1955? I don't think details of the Soviet gulag system were generally recognized (in the West) at that time. Solzhenitsyn, for example was not published until the 60's (except for samizdat versions of his early work). He was in a gulag himself until 1953.
I suspect Albert was unaware of the gulag system.
1. Appeal to authority -- apparently a big NO-NO, unless you're quoting a scientist :-)
2. Appealing to an authority on something that isn't even his specialty.
Full Disclosure: Yes, Einstein's IQ was supposedly 220+ . As such, yes, even without a degree in a field, he could happen to know more than many active practitioners, or even (like Feynman) undercut the whole area of study. BUT without advance knowledge of how informed Einstein was on an area, just blindly quoting him is not a good idea.