Not the entertainer, not the polarizing public figure, not the unwed father. Not that any of those topics should be off limits, especially a week before football's biggest game.
But if it's fair to criticize him personally, it's also unfair to let the criticism overshadow Newton's extraordinary talents. That is, after all, why the Carolina Panthers drafted him first overall five years ago out of Auburn even though they had just drafted their franchise quarterback, Jimmy Clausen, the year before.
Now Newton is the reason the Panthers, rather than Seattle or Arizona, are playing the Denver Broncos in the Super Bowl.
Before the violent beatings of the NFL destroyed his knees, his back and his shoulder, John Elway was considered the prototype NFL quarterback. Elway had all the physical gifts -- size, strength, powerful and accurate arm, mobility. He allegedly threw a football from one goal line to the other. He had all the intangibles -- intelligence, leadership, guts. For years -- until the arrival of Terrell Davis, Shannon Sharpe, Rod Smith and Ed McCaffrey -- Elway carried a mediocre bunch of Denver Broncos to three Super Bowls in four seasons. Elway finally won two Super Bowls when the Broncos got him some help.
Some still say Elway was the most complete quarterback of all time.
That might be about to change.
Consider the argument for Newton. He's bigger, stronger and more athletic than Elway. No, he didn't play in the New York Yankees' farm system as Elway did, but I'm sure some scouts would love to see what he could do in right field. Think Jason Heyward but maybe a step faster.
Here's the short list of the best Super Bowl quarterbacks since Elway retired, in no particular order:
Kurt Warner. Tom Brady. Peyton Manning. Ben Roethlisberger. Eli Manning. Drew Brees. Aaron Rodgers.
Which one of those is more physically gifted than Newton?
Brady might be the best ever. Peyton might be the smartest ever.
Newton isn't in their company yet. He might not ever be. Then again, he's still only 26. When Joe Montana was 26, no one thought he would surpass Johnny Unitas as the greatest ever. He had one Super Bowl ring, which many attributed to the genius of Bill Walsh as much as the ability of Montana.
But if Newton can stay healthy, there's no reason he can't be one of the greatest. Gus Malzahn, his coach at Auburn, made this very point last week on ESPN.
"He's got a chance, and I said this when he first came out, he's got a chance to be one of the best to ever play or the best that ever played. He's got everything. He's got a work ethic, he's just a great competitor, he's very coachable, he can run, he can make all the throws. He's got everything it takes. Everybody is seeing that now and it's going to be fun to watch."
Let's review that year at Auburn. It might be the greatest individual season in the history of college football. Without Newton, that team would have gone 6-6 at best. The 2009 and 2011 teams were a combined 10-10 against Power Five competition. The 2010 team went 14-0 and won the national championship.
"As the games got bigger, he played his best," Malzahn said. "He's got the it factor."
Newton carried that team, just as he's now carrying the Panthers. Yes, Carolina has a good defense. So do Arizona and Seattle in the NFC. Linebacker Luke Kuechly is one of the best players in the game.
But Newton just takes over games week after week. If the Panthers win the Super Bowl, it will be because the Broncos could not stop Newton. And if that's the case, Newton's 2015-16 season will go down in history as one of the greatest individual seasons -- maybe THE greatest season -- of all time.
So what if he pretends to rip his shirt off like Superman. So what if he pops up after running for a first down and signals first down. So what if he celebrates every touchdown with his little dance move called The Dab.
Newton gets criticized for his celebrations, but Rodgers gets a pass for his "championship belt" gesture. More than a pass, actually. State Farm paid him big bucks to parlay that into the Discount Double-check.
Newton has been criticized for celebrating the birth of his first child out of wedlock. You know, like Brady did with his former girlfriend Bridget Moynahan -- while he was beginning to date Gisele Bundchen.
All athletes have their critics. It comes with the territory. But all the haters would take him in a minute to lead their team. That is, if they want to win.
-- Guerry Clegg is an independent correspondent. You can write to him at email@example.com