The heckler’s veto is not freedom.

There are a lot of groups which coordinate spreading of lies to shout down others and deter others from contributing, firehose of falsehood style, and allowing that does not contribute to free speech. It does not support sharing facts, it doesn’t support healthy conversation, it doesn’t help anybody learn or discover the truth. Allowing conspiracy theories and nonsense like that is a net negative.

You need moderators who are focused on making sure people feel free to join in good faith.