There was references found in Greece of the story happening at the time.
Honestly how the fuck could we know?
But the part about God killing innocents, he did that shit a lot. Read how many groups of people the Jews wiped off of the planet.
Hell immediately after Moses brought the commandments down, they slaughtered a tribe of people.
The best way to even attempt to understand it is either by thinking God is a schizo or there were multiple Gods that were fucking with Moses's head.
Damn dude there are parts of the Torah where it will be talking about Jakob getting laid and next verse mentions talking trees and back to Jakob getting laid.
The Torah was weird dude.