Wait, did you just question the selection of an SPCT after said SPCT member criticized the company selcting him for SPCT by posting a sarcastic comment about there not being enough active GMs in-game and thus not enough actions taken against griefers (and blatant hackers too, btw)?
To answer your question, selection for SPCT is probably based on in-game activity, willingness to test, and quality of test feedback. Forum has fuck-all to do with it, and is to be considered as a stand-alone game/activity.