Something I'm verbalizing more however is that sexual male aggression and homophobia have more than a causal relationship. The young man acted out a horrible rape, and while racism and hate was there, I wonder if by "de-manning" the victim was more than meets the eye here. The more I study rape, (just reading laypersons books)the more I find the male rapist with a unrealistic view of what a "man" is. They need to find their victims inferior, or not human in some manner. In rape culture one of the (many) problems is the expectation of rape. Women expect it to happen whether we know it or not. Men don't, but it still happens. Also, by using a object for the rape the rapist may have been psychologically removing himself from what might be considered a homosexual rape.
No excuses here. I don't believe there is a cure for this kind of behavior, it's a institutionalized social problem. If the man had used his penis for the rape it would have been viewed differently even if extensive damage was caused. And as you point out, if the victim had been female, the usual blame the victim litany would have been trotted out.
I read this essay by Dworkin ever so often (I'm sure you're familiar with it) but it gives me chills every time
http://www.nostatusquo.com/ACLU/dworkin/WarZoneChaptIIIE.html