The freeze “is designed to keep up the pressure,” Mr. Steyer said. Of Facebook and Instagram, he added, “they are by far the worst platforms in terms of amplifying hate speech, amplifying racist messages and undermining democracy.”
Mr. Steyer said he expected more celebrities, as well as groups and individuals, to hop on board the Instagram freeze as the campaign spreads.
A Facebook spokesman declined to comment.
The freeze effort began on Monday, when celebrities including Mr. Baron Cohen and Mark Ruffalo posted that they were part of the campaign.
On Tuesday, Ms. Kardashian West joined in.
“I can’t sit by and stay silent while these platforms continue to allow the spreading of hate, propaganda and misinformation — created by groups to sow division and split America apart — only to take steps after people are killed,” she tweeted to her 66.7 million followers, urging them to also freeze their Instagram and Facebook accounts.
In total, the campaign said at least 14 celebrities were taking part in the social media effort, including Jennifer Lawrence, Mr. Ruffalo and Kerry Washington.
Despite the backlash, some people were emboldened by the stars’ announcements. “I’m in!!” one user tweeted in response to Mr. Baron Cohen. “Facebook is destroying minds, friendships, families, businesses. The false information that is being believed by previously rational people is destructive beyond belief. It has to stop.”