not to sound trivial, but i think that your mistaken about the functions of the amygdala. fear is just one of the things the amygdala regulates. it's job is also to discriminate a bunch of other things essential to our survival, among them is mates.
your first link didn't disprove what i said; it just didn't address the relationship of the amygdala to sex. i didn't read the second link cause it required a registration and i didn't know how long that'll take.
i initially got my information from a psychology book. but here's a university study that says that with rats, "lessions in a part of the amygdala eliminated sex discrimination."