"You're the president," the Today show anchor told Trump. "You're not someone's crazy uncle who can retweet whatever."
Guthrie's comment came after she asked the president about why he had shared at least two posts from followers of the QAnon mass delusion to his 87 million Twitter followers that questioned whether 9/11 terrorist leader Osama bin Laden had really been killed.
His tweets prompted a widespread outcry, including from Robert O'Neill, the former Navy SEAL who fired the shots that killed bin Laden during the 2011 raid in Pakistan.
Asked by Guthrie why he had shared the tweets, Trump dismissed the question.
"That was a retweet. That was an opinion of somebody and that was a retweet," he said. "I'll put it out there. People can decide for themselves. I don't take a position."
Guthrie then made her comments distinguishing Trump from someone's "crazy uncle."
"No, no, that was a retweet," he responded. "I do a lot of retweets. "And frankly, because the media is so fake and so corrupt, if I didn't have social media...I wouldn't be able to get the word out.”
"The word is false," Guthrie responded.
One person who did have a response to the "crazy uncle" comment was the president's niece, Mary Trump, who this year wrote a book denouncing him.