Okaaaaay funlovin. You have just put yourself firmly in the category of "PTA type" I would run a mile to avoid and who would put me right off getting involved. Which is the whole point of this thread. And yet it seems like you really can't see it.
Pontificating that what you do is for the sake of the children and so rewarding, is actually quite aggressive. You are defending your activities by deliberately implying anyone who doesn't do them doesn't really care about their children. Nasty.
Getting sneery and accusatory about it being "bitchy" (x 4) to not like the PTA. I guess that covers having any doubts about at all, or not liking the pushy, sexist attitude that many of us experience from our PTAs. No no, unless we are assimilated drones, devoting our lives to the PTA, we are suspect and need to get a life (ironic!).
Are working parents speshul (sic) and different?!
I think the bitchiness is coming from you here. And that comment also carries a very nasty taste of derogation too.
Actually though yes, what is special and different about working parents, if you choose those terms, is that they have less free time. Sometimes a lot less free time than you could possibly imagine. And as allhailqueenmab has said so clearly, so do not know the ins and outs of everyone's life and it's not for you to decide if how they spend their precious time is acceptable.