In assisted suicide, people consent to die a dignified death on paper and after government's approval further medical procedures are performed by the professionals. I don't see any problem here. Similarly I would have no problem with humans killing animals if animals start consenting to be killed. That's not the case. Whole social acceptance of killing of innocent animals and condemnation of rape feels like a show were Murderers are pointing out fingers at the rapists with the sense of moral superiority.