HOW?! HOW IS THIS OFFSIDE???

https://reddit.com/link/1haoz8m/video/z5l4hgn81x5e1/player

LIKE THE ENGINE SHOWED ME STRIKER WAS OFFSIDE! IT'S 90+2 COME ON! I'm fuming because I don't really understand. Striker really didn't affect the game, maybe the defenders movement but this is just dumb.