However often fought by men, war itself has been personified as feminine longer than writing, in Mesopotamia as well as among the various Indo-European warbands. The Proto-Germanic root of war and guerra seems to have been feminine and of course guerra itself is feminine in modern Italian.
For what it's worth, I know we aren't trying to make Mussolini sound better for the next generation but female is just a cringingly bad/lazy translation here. Femmina should just be woman or, if you really wanted to drive home the point about his own vulgarity and the fact he's purposely avoiding the more common and respectful donna, something base and sexist. His imagery there is doubtless something about how she's really just waiting for a manly man (in tights!) to submit herself to.
Of course that all ended about as well as you'd expect, just from these lines alone.