It's real life because by RJ's response, he effectively confirmed that Milhouse revealed to the boards the real life fact that RJ is not a child molester. Without Milhouse, none of us would have known one way or the other.
For example, Ph, I can't say for sure that you don't club baby seals. Unless you (or, god forbid, someone else, but that's against the rules) bring real life to the boards and confirm that you in fact do not club baby seals, I have no choice but to continue living in the dark. And avoiding you while playing dizzy bat at boards tailgates.