https://arstechnica.com/tech-policy/2021/01/pro-trump-reporter-gloats-over-access-to-fleeing-hill-staffers-computer/
The real answer? It's nowhere near as bad in my opinion as the other implications of an insurrection. These systems are already poorly secured and also physically accessible by a number of other staff, so one more potential compromise is not changing much.
(Because, whilst users ought to lock screens whenever they leave their desk, I can understand why that wouldn't happen in this situation, so a central control would have helped.)
For example here, was this reporter already inside the Capitol reporting, or did he also enter the building together with the protestors?