I assume you are not intending to imply that prison rape is an unlikely scenario? Because its certainly a lot more common than lopped off members.

Yes, male rape being a joke is a problem. Given the rates of incidence I find it less pressing than the attitude of suspicion & blame around female rape victims. However, the abundance of man trapped in a gorilla suit about to be raped jokes shows how deeply embeded it is- say its detached from reality, but change the sex and it would not be considered amusing.

Given that they are two sides of the same coin though focusing on fighting the attitude around female victimes is helpful towards male victims, in that it involves changing attitudes to sex generally.