A lot of the reason that researchers focus on the male perpetrator-female victim paradigm (including, admittedly, myself) is that that's what you're going to be looking at nine times out of ten. It's important to look at exceptions to the rule (male-on-male is by far the second largest category) but you have to do so in a way that doesn't lose sight of the rule. You can't treat sexual assault as a gender neutral problem because it's massively gendered. With that out of the way, this is an issue that needs attention. The evidence that this issue needs attention is the ubiquity of prison rape jokes.