The entire purpose of the Post Count is to count the number of posts a user has made. While I understand and agree with Forum Games not counting towards it, if you turn it off for other non-spam (or spam games) forums then you might as well remove it entirely since it is no longer doing the only job it has. I am strongly in favour of making PC only viewable in someone's profile though, because it really doesn't serve any actual purpose once someone has more than a few dozen posts.
There is a huge difference between light hearted discussion and banter (which I assume is this subforum's intended purpose) and out-right spam (which we already have other subforums for, at least one of which does count PC). If anything, the removal of PC is more likely to encourage users to be more spammy since it gives the impression that it is supposed to be spammy (since the other forums with it off are spam ones).