Neither driver would comment on the amount of the fine, although The Associated Press reported earlier in the week that one was fined as much as $50,000, and sources told ESPN.com the driver was Hamlin.
"What I asked was what was the point of fining me if you're not going to tell anyone," Hamlin said Friday at Pocono, site of the Pennsylvania 500 race this weekend. "They said, 'Well, hopefully it will keep anyone from bad-mouthing us.' Well, no one knows.
"All this coming out is a positive thing. Even though they may not have wanted everyone to know, now that they do it's happened for a reason and it's going to make the sport better."
Newman acknowledged that his fine was the result of comments made after the spring race at Talladega Superspeedway in which he questioned whether the kind of racing on display is what fans wanted to see. The race race went 12 laps past the scheduled distance because of NASCAR's new overtime rule that allows for three attempts at its version of overtime.
Hamlin, who has been outspoken on several issues, admitted he was fined for multiple comments. In terms of the reported amount of his fine, he said, "There's been illegal parts in the garage that haven't gotten penalized like I did."
Sources indicated it was for statements at Michigan, where the Joe Gibbs Racing driver brought up a phantom debris caution after winning, and at Chicagoland, where he was critical of potential changes to the Chase.
"I might as well have backed off and saved my tires," Hamlin said after his Michigan win, in which the late caution erased a big lead he had. "No, I didn't see any debris, but I understand it's show business. I'm not saying it's accepted, but what can you do?"
Newman said he initially was frustrated by the fine, but upon reflection realized there had been warnings and what he said wasn't for the good of the sport. He had no problem with NASCAR not divulging the drivers' identities or amount of their fines.
"I think everybody can voice their opinion," Newman said Friday. "I think what NASCAR is telling you is be careful how you voice your opinion and where you voice it and the impact it has when voicing it."
NASCAR has said only that the penalties were for the sake of protecting the brand.
"It is the sanctioning body's obligation on behalf of the industry and our fans to protect the sport's brand," spokesman Ramsey Poston said in a statement. "Any action taken by NASCAR has nothing to do with the drivers expressing an opinion -- it's focused on actions or comments that materially damage the sport.
"We have specifically discussed this in meetings with teams, drivers and stakeholders."
Newman said it is important that all drivers understand this.
"I don't want to talk about the negative," Newman said. "NASCAR doesn't want to talk about the negative. We're here to put on great races for the fans and enjoy it with your family so you will go home and talk about how much fun they had so they'll want to come back next year.
"I was frustrated about it, mostly because I didn't understand what it was and why it was. It's behind me. It's behind Denny, I think."
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org.