TikTok is the main place pro-Palestine viewpoints went viral. I don't know whether this is because of the demographics of users, or because US platforms were putting their thumb on the scale, or because TikTok was putting
its thumb on the scale, or just randomly, but it is in fact the case.
So that's one quite mainstream opinion that would be suppressed if the government banned TikTok. No, you wouldn't be arrested for posting pro-Palestine stuff to Facebook (at least not under Biden...) but that's not the only way for the government to curtail speech.