Except it's not a bar, it's a web site where you only interact with people you have affirmatively decided to interact with.
It's like if there is a Nazi living in your apartment building, and specifically forbidden by the laws of physics from doing anything physical to anyone or making any statement or posting any literature to anyone who hasn't decided they want to hear from them. The risk of everyone in the apartment building deciding to become a Nazi in that situation is small.
I actually agreed with their viewpoint, and the fact that they had to backtrack after a noisy section of the community blew up at them, and that noisy section of the community decided that they were still bad people even though they'd backtracked, and now are "soured," is to me much more of an indictment of that section of the community than it is of Substack.