This would be an uprising; it's being called a "coup" because uprising sounds sympathetic.
But people need to be careful, because by saying it was a coup, it normalizes the concept for those who saw Wednesday as a good faith protest march, regardless of what it's now perceived as.
Changing/ shifting the definition of words has behavioral consequences.
But, really, it was a protest. The point was to engage in drama and theatrics. Why break into the Capitol? Even more drama.
Now people are dead, it's managed to tar even Trump's public image, and they're going to get hit with federal charges.
Supporters of BLM have committed far worse acts in recent years but they are not labelled as terrorists. The only people that died at this event were the protestors - one at least was unarmed and murdered by a police officer. The whole thing is on video.