How about we argue instead that discriminating is wrong, and we shouldn't actively promote it.
Secondly, I would argue that your list, from my point of view, denoted 'racism, sexism, etc' is more rigorously defined as 'discriminating based on anything other than merit'.
Given that assumption, discrimination by race or sex for any reason would be wrong.
With those premises, I stand by my original conclusion that discrimination on the whole is wrong.
My comment nextdoor describes my problem with these sorts of degenerate defintions: http://news.ycombinator.com/item?id=5350842
To put it another way: if your definition of sexism means that women-centric events designed to foster interest in an otherwise underrepresented field is considered sexist, then its your definition that is faulty.
Here's a definition that doesn't strip the salient context from it (dictionary.com)
1.attitudes or behavior based on traditional stereotypes of sexual roles.
2.discrimination or devaluation based on a person's sex, as in restricted job opportunities; especially, such discrimination directed against women.
It's amazing how these discussions always devolve into cherry-picking definitions and parsing language like a machine to prove respective points. If you have to resort to that, then just bow out gracefully as you are missing the point of the discussion altogether.
To put it another way, the ends justifies the means. And I think you'll find plenty who would disagree with that statement.