BLM protesters were murdering for months?

If "BLM people" were calling for murders in public in the same way these Capitol people have been, then absolutely they should be kicked off platforms. I don't think many would disagree with that.

The sufficient cause in this case was that Cletus went on to invade the Capitol, driving the entire Congress into hiding for hours, while demanding (literally - some people were chanting the exact phrase) "heads on pikes". If it were just an abstract speech issue, I'd absolutely oppose Amazon's actions here.