I think most atheists would agree that Jesus sounds like a great guy.

The sticking point is probably more the lack of actual evidence for a deity existing, plus the general observation that, judging from history, religious groups tend to act as if "gain political power and/or go kill that other religious group" is the highest calling.

For that matter, if Jesus returned and resumed his ministry in the modern USA, I'd actually expect more Christians to be "scandalized" than atheists.