Among those upset was Scott Dixon, who said Indianapolis 500 winner Tony Kanaan ran him wide on the last restart and then didn't buy his post-race explanation that it was unintentional.
"We had some words. He said he didn't mean it, but it's pretty obvious what he did," Dixon said.
James Hinchcliffe, meanwhile, lauded Kanaan as one of the more respectful lapped cars and said others were clogging traffic at the end of the race.
"There are some guys out there who are a lap down driving like it's the last lap of the race for a win," said Hinchcliffe. "Other guys, like TK, super respectful, let me by. But other guys ... if they keep ticking people off, it's going to come back and bite them."
But IndyCar points leader Helio Castroneves, the runner-up finisher, said lapped traffic was a problem for the final 12 laps of the race. Castroneves said part of the issue was the lapped cars were not being signaled to move out of the way by the flag man.
"The problem is I can see the blue flag. In all fairness for the lapped traffic, they're not waving, they're just put in position," Castroneves said. "But sometimes people need to use courtesy. Kind of like, 'Hey, let a guy by.' Unfortunately for me, it wasn't that case."
Asked if he'd spoken to any drivers in particular, Castroneves said he wasn't ready.
"I think I need to let my blood pressure go a little bit down," he said. "I was a little bit upset. It was just upsetting my car a lot. But, anyway, we talk about this at the drivers meeting sometimes. If it's middle of the race, maybe it's fine. But 10 laps left in the race?"