Christians, how do you explain the horrible atrocity that...?

The children may have been young adults. There's no Hebrew word for teenager, but it's umed young children weren't roaming around in a pack. Teenagers do this. The phrase "Go up" is a colloquial death threat. If you look at it that way, you have a group of teenagers threatening to kill the prophet. They messed with God's man and got what they deserved.