Why is it, if there is no God, that atheists are so viscerally hostile to those who believe there is?
It’s because they do indeed know that there is a standard of behavior, that there is a standard Giver, that they are not living to that standard, and will indeed be judged by that standard Giver.
It’s part of our created nature to understand these things.
No, it's because some people are arrogant bastards who have no respect for others. The most outspoken, fundamentalist types tend to be that across any ideology.
that they are not living to that standard, and will indeed be judged by that standard Giver
And their behavior is exacerbated by other arrogant bastards telling them they aren't living up to some moral standard that includes sanctioned slavery and genocide.