Because there's no comparison? When I see someone eating a hamburger, I'm like "whatever", when I see someone sticking their dick in a hamburger, I want to punch them in the back of the head.
Fucking a dead body is perverse, eating one is eating one. You can only be so disgusted by what someone eats, you know, if they're eating a shit then yeah that's fucked up, it's really bad don't get me wrong, but if they're fucking a shit, well, that's just infuriating. How dare they?
What someone wants to do with a dead human body just says a lot about them. If someone's first choice would be to eat the body, what do we learn? They're hungry? Who cares. At worst they're inclined to disregard our social standards that state you shouldn't eat people, whatever really. I personally would choose to tape the dead body to a stick and shake it at children to frighten them, so I also disregard social standards, I'm just not hungry.
In the case of choosing to fuck the dead human body, to hump it untill you orgasm inside of it/on it, that too disregards social standards, PLUS it's a disgustingly perverse choice and the person who makes it is clearly scum.
This should be so strongly hardwired into everyone that it needs no further explanation, if you see someone fucking a dead body you see someone making the most disgracefull choice possible, and proving themselves to be the worst kind of person on earth, no contest.
Even asking the question, "why is eating a dead body better than fucking it?" makes one raise an eyebrow at the person asking it. Why do you have to ask that?
Weren't you also vocal in supporting the sick freak who was effing his comatose wife? Are you deranged by any chance?