"Unlike undocumented immigrants, John McCain, or Rosie O'Donnell, the Fox News anchor enjoys a huge following among the network's viewers, who happen to make up the core of the Republican primary electorate," they said.
"So picking a fight with Kelly - as Trump did when he chided her during a tough debate question about insults he's lobbed at women, dissed her in the spin room, and tweeted his complaints about her - carries risks that Trump's other feuds do not."
Hours later, the leader of the annual Red State Gathering in Atlanta announced on Twitter that Mr Trump was no longer welcome at the weekend event - and Miss Kelly was asked to join the conference in his place.
"I have rescinded my invitation to Mr Trump. While I have tried to give him great latitude, his remark about Megyn Kelly was a bridge too far," said Erick Erickson, the organiser.
"His comment was inappropriate. It is unfortunate to have to disinvite him. But I just don't want someone on stage who gets a hostile question from a lady and his first inclination is to imply it was hormonal. It just was wrong."
Later on Friday night, Mr Erickson told the Daily News he made the decision out of "common decency."
"I mean, come on, you're going to accuse Megyn Kelly of having her period and that's why she asked the tough questions ... I just think that's crap."
