Given the rule this forum set up about plagiarism, I think even not here or in real world we can see that this is not acceptable and sometime could sue you if you invade copyrights isnt it? So thats why it strict here and the punishment is perma ban.

Ive hear some cases of plagiarism for higher ranks but given the situation, evidence and fact, and contributions the decision can changed. For example. You are a good contributor and quality poster and later on got found out of plagiarism. Its case to case basis for your ban.