That statement seems technically correct, if only simply due to the passage of time; but cheer up, it certainly does not now prevent charges based on violation of various state statutes.
Meanwhile, the Constitution does provide for the Jan 6 Joint Session of Congress. That session was to be held after the "fact" for the sole purpose of objecting to the votes of the various states prior to inauguration.
With that, one can only speculate as to the basis for the decision by Speaker Pelosi to not provide additional security when such was thought warranted by her Capitol Police downline. It was her call and perhaps her call alone.
And the sitting president (Trump) offered a very large amount of protection because he said it was going to be the largest amount of people he ever spoke in front of. Her not accepting it was proof they wanted and likely were planning something. Now they are seeing video from inside. Showing what looked to be police letting people with Trump signs inside the side door.