Dahmer was a sociopath. He enjoyed necro sex. But, his prime motivator was domination, torture and murder. He was also very self sufficient whereas we just admire his work and that of others. I think you would be surprised just how normal it is to be stimulated when viewing dead men. It's very primal to kill other men to claim a mate and sexual domination of men was often part of being the winner of a conflict. It's been that way for thousands of years. Who are we to deny nature???