>He doesn't allow doxxing out of a commitment to free speech.

To rephrase that sentence: Free speech isn't the reason he allows doxing on the forum.

Do you have a source for that claim?

It's like I explained above. It's safe to assume they don't care that much about free speech, because Null has banned people for dissent.

An example: https://ghostarchive.org/archive/JcaLQ

I don't think a free speech absolutist would secretly ban people for criticizing him.