True Story: Try Not To CryðŸ˜

I relate the en passant rule to the not being able to castle through an attacked square rule, in that the en passant rule exists because your pawn isn't actually "jumping" a square it's moving two squares I'm one move so in theory your pawn was in the square in which it could have been captured. I think that's a decent explanation for someone who is completely unfamiliar with the rule