Is double pawn a bad structure?

The worst recorded is the quadrupled pawns:
https://youtu.be/3M_h4yJ3IuM

Has anyone of your expensive trainers mentioned that every doubled pawn provides an open file which is often a valuable asset!?

@Sarg0n It can open files for the opponent also, I think it's not possible to say "double pawns are good" or "double pawns are not good" we have to look at the game where it happened because every position is different and in some positions the double pawns are good, in others the double pawns are not good.

A bad structure for what? In the middlegame at 1500 lichess rating it doesn't matter. In the endgame it would be somewhat bad structure because it's more difficult to defend than connected pawns. But even if you lose 1 of those pawns it should not be a problem.

@pointlesswindows If you lose a pawn the game is usually over.

@Krukulu You didn't read. I said on 1500 level it does NOT matter if you are 1 pawn down.