Look at it this way. Think of the squares as land. Chess was/is a game of war. It may be a mental one fought on a board but the idea is ground war since only recently did we invent flight, machinery, automobiles, etc. It used to be a battle mainly on land (& mainly on foot) gain a bit here & there, lose some, etc. It only seems logical that pawns (the lowly foot soldiers) should fight for terrain before conquering it, bypassing it. If the opposing pawn has spent effort & time (that IS a price/cost) reaching the 5th rank (ur side) it shouldn't be possible to simply disregard its existence & move past its influence without first addressing it & the square it attacks. U should have to at least compete for it. So consider the squares as plots of land to be acquired. Besides, if en passant didn't exist then almost all games would end up as draws because all the pawns would get locked up.
Ok, that resolves this thread & all others similar to it, which have been many. Ur welcome.
i would but now @mattew is also waiting for it - i cannot disappoint him or he might not respect me. and i'll all about respect.
https://www.chess.com/forum/view/off-topic/jalex13-avez-vous-mangez-vos-escargots