Ok, I have an alternative argument for you that is equally tenable and equally flimsy. Try this:
Back when colour vision evolved there were no white or pink people (with the possible exception of the occasional albino). All people would have been black, and possibly hairy. In a social primate group, the females would be involved with supporting other females who were giving birth. Similar behaviour is also observed in elephants and other species, so this is not a far fetched conjecture with regard to our ancestors.
So, the reason women are hard wired to prefer pink is very simple. When playing midwife for someone who is black and hairy it is important to pay attention to the pink bits.
My logic is impeccable.
Devious, treacherous, murderous, neanderthal, sub-human of the West.