first statement was sarcastic: my real statement is that hating on stuff that teenage girls like is not cool but is seen as cool by wider society. see the hate on boy bands like jonas brothers. hate on twilight books. and so on.
I personally think ridiculing stuff like the Twilight books is fine, if you do it on the merit of its writing and questionable plot elements. You are a dick if you just complain about it because it's for girls, and "girls are stupid", but ridiculing crap for being crap is not an inherent bad by itself.
We sadly live in a time where a lot of media directed at teenage girls legitimately IS crappy and shallow, not because "girls are stupid", but because the whole market is driven by old, male, out-of-touch non-artists whose ideas of appealing girl content end at "make everything pink, vapid, and about makeup/crushing on boys". If someone tries to create something genuinely thoughtful and intelligent for the young girl demographic, chances are those decaying fossils will just laugh them out of the building for not considering profit margins. Not the fault of teenage girls at all, but it is what it is, and it will not change until those people are kicked off the board or die off.
I don't let that stop myself from finding stuff like the transformers movies or other generic male-fantasy crap equally as vapid though.
I've seen people shit on My Little Pony saying "you watch this show aimed at little girls" and I never see this the other way around. Hell, one of my IRL friends doesn't openly like admitting that he loves MLP in public and it's a shame he is embarrassed for liking it when I equally like shows aimed at little boys such as Transformers but I'm less embarrassed for liking it.
The "not like other girls" thing is something made up by old white men executives btw.