He has known about Q for a long time, several months ago, he posted a poll on #followthewhiterabbit, which was deleted shortly thereafter.
I believe him and jack both knew about it, but tried not to say something about it, and/or spun it towards larp. I also believe they were directed to do so, by white hats. Before you attack me on this consider that both of these guys have both received many good scoops over the last year, and Jack also got shouted out on twitter by the POTUS.
Q wasn't ready to go mainstream until now, but by JP even mentioning Q was a larp it brings exposure to it, it doesn't matter if he says it's a larp or not.
If nothing else them bringing it up helps our cause tremendously, it doesn't matter if they believe or not. What matters is the exposure, and us bringing the proofs to show people the truth.