I think it's a case of "Hey man, you can't joke about that, my father died that way".
Only if that discussion explains how that joke in any way trivializes rape or makes fun of rape victims for being rape victims*. Maybe I'm just weird, but when a comic is mentioning rape as an example of something horrifying and torturous that it is ridiculous to even passively condone, I find it hard to take seriously the argument that the comic is somehow trivializing rape. Or that it makes the artist a rape apologist.
*kind of an important distinction! Being a rape victim doesn't confer a special magical status where stupid shit you spray on the internet becomes immune to criticism, and making fun of idiots for being idiots doesn't take on a misogynistic aspect just because those idiots are also rape victims.
I think there's also the argument to be made that the reactionary way that feminism is handling the topic of 'rape culture' is just making a lot of sensible people roll their eyes. The end result of this is that when someone complains about something legitimately fucked up, like rape in the army which
actually is perpetuated by a culture which
actually does promote rape, it's harder for people to take it, and it's victims seriously.
Again, this whole thing feels less to me about people taking genuine offense at something they found genuinely offensive and more about radical, militant feminists deciding what we should and should not be able to talk about. I view these arguments the same way I do religious fanatics and racial supremacists. The fact that this was taken as seriously as it was by people bothers the hell out of me.