Is this plagerism? (MODERATOR, PLEASE TELL ME!)

you should have him make his own account on here and post it himself. The rules clearly state that you are to post only your own work. I have asked Janis this personally. Even if it's a friend that says, "please post this with your poems" you are still not supposed to do it. (Yes, even if you give them credit)

*As for the original question, I wouldn't necessarily call it plagiarism...but it is breaking the rules

Oh dear...

I never really understood it either, but I guess I kind of do. Citing the author doesn't mean you have their permission to post it, and just because someone says they have permission doesn't mean they really do. So you cover all your bases by making a blanket rule of "post nothing but your own work".