> There was not a peep about their content until from their reps until 1/6. Was it the riot or the senate flipping?

Sounds like you answered your own question. Tech companies were lenient on hosting a questionable community, until members of that community tried to overthrow the government. For all the moderation the Parler admins allegedly did, it was an open secret that it was the hang out spot for right-wing extremists. Yet Parler was allowed to stay afloat until it became clear that doing so became an issue of national security. The riots happened. The cause and effect here are pretty clear. The Parler community did this to itself.