Facebook, Twitter, and Google have not tried to take a stand against moderation; the worst you can say is that they still need to improve their moderation polic

Facebook, Twitter, and Google have not tried to take a stand against moderation; the worst you can say is that they still need to improve their moderation policies and techniques. Parler was created as a protest against the moderation that happens on other platforms, to be a place where the people who are too extreme for Facebook etc. can communicate, recruit, and so forth. Likewise with Gab, which was created in response to Twitter's own efforts at moderation. Nothing unequeal about the treatment, because Parler's efforts at moderation were never equal (in either commitment or scope) to the other platforms you mentioned.