Argument
Patriarchy and bias in the law.
It seems biased, seeing as though rape is generally targeted at women. The way the law is now, it favors the rapist over the victim, the former usually being male and the latter female. Lay low long enough and your crime just goes away. It's a sprout from the tree of rape culture and male patriarchy that needs to be pruned.
On the contrary, men have a greater chance of being murdered, but no statute of limitations on that.
If a woman is raped by a man (or just says she was), she immediately gets sympathy, whether she was a victim or not. People side with her, whether she is a victim or not.
I'm not saying actual female victims don't have their own problems like victim-blaming and not being believed sometimes. But people know about it. People are fighting for them, as they should. But who fights for male victims? Nobody, because society paints men as pigs that want sex 100 percent of the time. Females complain about being slut-shamed, as they should. But men are slut-shamed by default.
Also, murder doesn't have statue of limitation because DNA evidence involved in the case doesn't easily go away. The victim's corpse in of itself is evidence. The victim can be identified by the teeth alone, even if it has decayed/been damaged by cause of death or desposal method.
In rape cases, once the victim washes majority of the DNA that could be used is gone.