OK found it - NeanderChap. One post.
I agree (still!) that the female behaviour he describes is anti-feminist. I posted, as have others, that there are plenty of stereotyped male behaviours that piss me off, as well. However this isn't about those; it's specifically about the babygirl act described in the OP, and which the majority of us have witnessed frequently IRL.
When a bright woman tells me she's too stupid to do a thing, or a woman calls herself ugly, I feel sympathy, pity and anger. The anger is because somebody made her believe she's inadequate. I would tend to assume, lacking other information, she received that message due to patriarchal influences and quite likely from specific men.
By contrast, when a bright woman puts on a babygirl act to elicit help from a man - or flirts inappropriately - I feel a lot less sympathy for her. My view is that she's perpetuating a "big man, little woman" stereotype. I assume she does it because she believes men are fools who can be manipulated easily by women who appeal to them by being both sexy and childlike. I dislike manipulative behaviour; I dislike conflations of sexiness with childishness; I dislike sexist assumptions. Therefore, I dislike this act.
To me there's a chasm between the woman with 'damaged' responses and the one playing the game. I understand that, in a patriarchy, the game actually can actually work. But, to me, this fact doesn't excuse the behaviour. I would like to see everyone asking women who do this to repeat themselves. Since some men are fools who fall for it, it's down to those who aren't so dumb to do that work. I wish someone had suggested it directly to NeanderChap.
I probably need to reiterate that I've got no problem with women whose voices really are 'babyish'. Julie Burchill's voice comes in for a bit of flak around here, but it really is her voice and she's as entitled as any other woman to speak with her own voice. But I can't pretend there are no women who put on a 'helpless little me' act - deliberately - specifically in order to work a sexist stereotype. I do not support those women in their manipulations.
You could say "If it works, why not do it?" My answer would be that asking a sensible question in your usual manner works, too, so why not do that and leave the gender stereotype out of it?