A question about a condition called postural orthostatic tachycardia syndrome, or POTS, upset many viewers.
The “Avengers” star also revealed how her mother, Blythe Danner, feels about Goop selling vibrators.
Earlier this year Trump congratulated Welker on a promotion, and a senior Trump campaign adviser called her "very fair" and an "excellent" choice as moderator.
“I’d like to start by tearing you a new one," McKinnon tells Alec Baldwin's Trump at a redo of the NBC faceoff.
The Trump-loving Fox News host said the moderator's questioning of the president was "pure political bias" and "not journalism."
"You’re the president; you’re not like someone’s crazy uncle who can retweet whatever,” the host said at Trump's NBC News town hall.
The president also praised supporters of the outlandish conspiracy theory for being "very strongly against pedophilia."
The president also personally attacked Savannah Guthrie, who is expected to moderate the event.
"Hopefully next time I see you, I'll really see you!" the co-anchor said.
He was "the guy you wanted by your side no matter where you were,” NBC News Chairman Andrew Lack said.