The "Lighten Up" situation is quite different in that there was an identifiable victim of the sexism who suffered concrete consequences such as being forced to attend an HR meeting. "Every woman in CS" is too broad to establish an identifiable victim and "this makes me angry" is not a concrete consequence.
Sure, but the point of the 'Lighten Up' is that just because someone doesn't speak up doesn't mean that they don't feel disenfranchised. In fact, that is the frustrating point for Katie, because by speaking up, one risks being branded (or, at least, told to 'lighten up')
Hypotheticals aside, the biggest problem with your argument is that you seem to be saying that if the OP was a woman, then she'd have more of a point...I hope to think that isn't the case...if the OP's point is flawed then it is wrong if it comes from a woman.
(in the abortion debate, the "men should mind their own business" sentiment is also flawed, especially since there are a good number of women who oppose abortion)