IIRC, theymos/a mod already stated that plagiarism is plagiarism and it doesn't matter how much posts/reputation someone has. Also, he didn't get a permaban like most users, so that's something.
This also (kind of) answers another question:
https://bitcointalk.org/index.php?topic=5113076.msg49868535#msg49868535Does this mean that users with plagiarism before 21/11/2016 should not get banned?
It looks like plagiarism before 2016 - when it showed up in the list of rules - is still considered unacceptable, although the ban is softer in this case.