"I suggest you watch the 2nd link, the discourse with Audioholics and Emiko (who also hails from pro audio) and see if they thought everything was fine and dandy on this ad."
I'm with those who think the ad is fine. I think some people may be viewing the ad from and audiophile's perspective, and audiophiles (like Emiko) are not the target audience. JBL is clearly aiming the ad at entry level audio consumers, and specifically young women who have traditionally not been their customers. So what's wrong with that?
It may seem like stereotyping but, for whatever the reasons may be, women (in general) have not been audio equipment consumers much less enthusiasts. JBL is obviously looking to change that. As I see it, the young women in the ad seem to be a fairly accurate representation of that target group.