Okay, I've spoken to a moderator (keeping them anonymous) and it honestly seems that, from what I've gotten, there's a misunderstanding with thinking that COPPA applies to showdown: It doesn't.
The Showdown rule regarding COPPA was removed ages ago by Zarel. I believe there's some sort of confusion regarding rule #2 as far as "follow all US laws" but i believe that is in regards to "Don't distribute pirated material, and don't slander others.", as far as my understanding comes out of it. It is also worded that PS is available to users under 18, which includes those that are under 13 as well.
I apologize if this wording is poor, I hope I clarified the best that I can.