Yuo're right to some extent Rapaire, though there are few goddesses that are specifically "War Goddesses." But many deities of either sex had their violent streaks for various reasons.

Most of the deities who's "lives" are commonly found in European mythology were the major gods what were worshiped on a large scale, by nearly all the people in the particular culture (Roman, Norse, Celt, etc.) Because war is not a new idea and is (ironically) as human a trait as preservation of the species, it is natural that there would be gods of war - but most cultures had male gods of war.

There are variations, of course. To me one of the oddest things is that both the Japanese and the Finns consider the sun to be feminine and there primary deity a sun goddess.