They shot a terrorist that was actively breaching the capital building.
You say terrorist, I say vandal and miscreant. But hey, I'm sure your precogs knew exactly what she was going to do.
I prefer seditionist in that they: 1) took over federal property, 2) attempted to prevent the lawful certification of the election of the President.
If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined under this title or imprisoned not more than twenty years, or both.
I am glad that there was not more loss of life. That the Capitol police were underprepared and/or supported seems pretty clear in hindsight, especially given the crystal clear messaging of what could be a worst case scenario ("It will be wild." The legions of social media posts about how to get weapons into DC, etc). Trump's response to the rioting was abhorrent, but entirely consistent with years of statements ranging from "very fine people" to "stand by and stand down" and finally to "we love you."
Falling back on whataboutism and false equivalency to the BLM protests of the summer reveals a lot about people and how they view these events. The events of Jan 6 ultimately stand on their own, and no amount of rationalization will make it okay or justifiable, or less than outright attempt to subvert the democratic process central to our nation.