My read is this is much less about the Capitol Police response and more about what the DoJ and its associated organizations like the FBI, did next to nothing, despite having plenty of evidence that this clusterfuck was brewing.
And that’s an investigation that is going to take awhile, and be plenty ugly. I think we’ve already seen the reader’s digest version…numerous Trump appointees shut down and aggressively attacked anyone that attempted to paint white supremists or Trumpers (a Venn diagram that far too often looks like just 1 circle) as a threat. So, when lots of blinking lights go off, the response was “Yeah, but those are our guys”.