Anthony Barr says don't do it ... 'cause that's dumb -- and people just need to MOVE ON!!!

"Sorry," the Vikings star tells TMZ Sports ... "Take your L and keep pushing. It happens. It's unfortunate, but it's the world we live in. It's not perfect."

One Saints fan clearly disagrees ... a guy actually filed a lawsuit Tuesday suing Roger Goodell and the NFL for not taking action over the non-P.I. call in Sunday's NFC Championship Game.

But, Barr -- who says he certainly understands the pain -- tells us court action is taking things way too far ... and says everyone in NOLA just needs to let it go.

"You can't replay a game after the results are in."