Its completely rational, because as you said its a huge shadow on the perpetrator's morality and humanity that they can do that and we should want them punished for being so heinous.

But, the guy who can push a button and accomplish the same net end is almost eviler. Because he is so detached from the situation he isn't even giving human life the intimacy it deserves when it takes it. He can laugh in complete safety while he murders dozens, whereas the butcher is taking a risk everytime he does it and having to look at the horrors he leaves behind.

Its a normal reaction to the situation to think like you do, but I think that once we detach ourselves from gut instinct we can evaluate it to be a lot different than our minds think.