A boycott of links to Mr. Musk’s social media platform spread on Reddit this week, after he made a gesture that some likened to a Nazi salute. Others worried about censorship.

After Musk sparked a wave of ire with back-to-back Nazi salutes at an Inauguration Day event in Washington, D.C., on Monday, the bans quickly swept across Reddit. Such a move is not unheard of — moderators can ban links to specific sites, meaning that posts and comments including X links are easy to block.