Yes, definitely justified! If you don't want to be shot, don't be part of a massive mob rampaging through the capitol, breaking glass, busting through doors and trying to enter the secure area behind the house Chamber itself as representatives are being evacuated!

"Waaa! They should have pepper sprayed her! They should have used a taser!" as hundreds of rioters are swarming the building. The right wing became such humanitarians all of a sudden! Gimme a break!

POP!

And I notice suddenly no one else attempted to climb through after that. Seemed pretty effective.

No reason to identify the officer and plenty not to!