Shortly after Thursday's first Duel, Petty was asked innocuously what he thought of all the two-car drafting that made up the 500 qualifying race. Petty replied tersely that he couldn't stand it and that he was "ashamed to be a part of it."
In a nutshell: the drivers are approaching the race like a road race in cycling, by taking turns drafting the front car. This is huge because in most of auto racing each driver is on his own, they may talk to their pit but not to other cars in the team. Now you have cars coordinating who stays in front and who drafts. The drafting itself is not an issue, it has been a strategic part of NASCAR racing since forever, the problem is that it is coordinated, and that the trailing car relies too much on the lead car (they can't even see ahead because they follow so close). Pack drafting is OK, coordinated in-team drafting isn't.
They are also bitching, and this is a good one, because the track was repaved and it is TOO GOOD. Yes, they are complaining that the repaving cleaned up the bumps and whatever else that made the track unique.
Haters gonna hate.