I'd say the same about CloudFlare some time ago when it comes to blocking "enemies" that are not explicitly breaking the law, but here we are. Never say never, and even if an organization would never do such a thing today, who knows who is controlling the organization tomorrow.
TOS and documents like that are written by lawyers. What an organization might or might not do in practice has almost no bearing to their "subscriber agreement" and other legal documents.
Yeah, here I thought the same would happen if technology companies started banning people without any anti-criminal justification but again, here we are. Parler built a platform that could be used for bad, so instead of letting the country deal with the bad outcomes of the platform (like how we deal with Twitter and Facebook), the "modern" western world decided, without any intervention from the government, that Parler is not allowed to exist anymore.