It could be many reasons. One that comes to mind is OPSEC. Maybe the clowns would have an easier time compromising the locked board than the others due to its more-static nature.
Secondly, Q would have to post then change boards to reply or clarify. By staying in /qr, Q can be more immediately involved in the responses and likely miss less than he would were he changing boards.
Lastly, maybe he's not posting in GA because he found it doesn't really perform a vital function. With github making noises about shutting down qcode, it is likely that GA might become important again shortly.