Wahlberg told TVGuide.com: "There's a stink being made because certain people aren't happy with the way they're portrayed, but the reality is that in most cases, the producers took a gentle hand (and) were very careful to not make it look one-sided or make people look bad."
He also said the series only offers an unfortunate but true look at the decisions leading up to the Sept. 11 attacks.
"There were mistakes made, by many people. And those who see themselves portrayed in it, they're going to be sensitive about it. But everything's different in hindsight," said Wahlberg.