In my opinion, it’s slightly better than Just Fucking Google It, which serves no other purpose than being patronizing. LMGTFY actually gives results.
If it popped up in the Game Room, I’d OK it, barring extraneous snark. For instance, a single LMGTFY link in the post would go through but a “LMGTFY link, dumbass” wouldn’t.
Of course, I’ve been brought up with the “google twice, post once” rule. YMMW.