As you noted, the greater prevalence of right-wing violence, hate speech, and disinformation/misinformation causes the appearance of a moderation bias against conservatives. However, there has been an actual measured bias in favor of conservative voices (circa late 2021, the home timeline algorithm may have changed since then).
In other words, conservatives do more stuff to run afoul of the terms of service, and they also receive better treatment. GP is wrong/misinformed.