Conspiracy fact. I watched on video as cops moved barricades to let rioters in, took selfies with rioters, then literally held the hands of rioters as they walked down the capitol stairs.
Thanks, but that's not what I meant though. What that person described was that an unusually low, insufficient level of security had been established before the event, in comparison to any other run of the mill event that had taken place in that area in the past. The exact opposite should have been done, since everyone expected there to be trouble.
In terms of conspiracy theory, there are two possibilities I can think of: a) someone in power under-secured the event in the expectation that the riot would succeed and become a coup, or b) someone in power under-secured the event in the expectation that the riot would not succeed but would be enough of a spectacle that it could then be used against the people who were involved with facilitating and encouraging it. However, this all hinges on that observer's evaluation being accurate that the event had indeed been unusually under-secured.