Yes, the regular refs made mistakes too, but some of the ones the replacement referees have made are down right embarrassing. They've fumbled numerous calls leading up to Week 1, including calling a touchback on a punt that was clearly down around the 5-yard line. The call was so bad, the NFL got the evidence taken off Youtube; or at least tried to.
They put two footballs out on the field, can't get their words out in a clear sentence and—according to Mario Williams—refused to call face mask penalties during Week 1's Bills vs. Jets game. Many of the replacement refs have never officiated D-1 games, only D-II or lower and you can tell by how they huddle up after every call. Some have even officiated Lingerie League "football games," if you want to call them that. During the Seahawks vs. Cardinals game, the replacement refs gave the Seahawks a fourth timeout with 30 seconds left. That gaffe almost cost Arizona the game if it wasn't for Braylon Edwards letting a ball slip throw his fingers in the endzone. Oh yeah, on top of all that there was the Broncos vs. Falcons game. SMH.