I think there has to be a caveat here, because not every militaristic culture has fitted the pattern of our modern misogynistic and homophobic culture. Sparta and Athens come to mind. Most cultures seem to fit this pattern, though. I think it is more of a correlation than a causation.

Even so, there seems to be a pattern of stylized (and therefore dehumanizing) sensuality and/or violence in most empires. The Aztecs had the only openly cannibalistic empire I'm aware of, the rest of them seem to cannibalize only subliminally.