Maybe my viewpoint is skewed by a practical and pragmatic engineering mindset coupled with a 30+ year career in and around the DoD. Dead is dead. It doesn't matter if it is from a nuclear weapon, a conventional bomb, an IED, or a single aimed bullet. Dead is dead. Nuclear weapons differ only in scale and some side effects.
The horrific part of this isn't that we dropped nuclear bombs. It isn't even that we had to destroy entire cities using nuclear weapons, conventional bombs, napalm, whatever. The true horror is that we had to go to war at all - that the situation degenerated into "we have to kill enough of your people and destroy enough of your resources to make you change your ways." That's the real horror. Everything else is just implementation. Who was it that said "It is well that war is so terrible, lest we should grow too fond of it?"
Anyway, to me, there is nothing particularly more or less horrifying about nuclear weapons.
Robert E. Lee