I suppose one could argue your scary example has already occurred. I believe stripe cut off Donald Trump [1]. As a non-American, I don't really care about Trump and may be a bit ignorant here, but I find the big tech companies cutting him off under "inciting violence" a bit of a stretch. To me, it's actually extra scary to cut off a politician's fundraising for disagreeing with their "politics".
[1] https://www.wsj.com/articles/stripe-stops-processing-payment...