The moment the guards were deployed as part of arrest operations with ICE, like at the park, it was not legal under PC. That's not just my opinion; CA currently has a lawsuit asserting just that.
The deployment of them in DC is another pseudo-legal deployment, the point of which is to normalize NG units being deployed into other states.
Newsom isn't the Left, but unfortunately the 'true' Left is being just as feckless as the neolibs are. The disavowal of anything but perfect pacifism may be pure rhetoric in some of their minds, to shield them from being scapegoated, but the net effect is that the Left and the neolibs both are at least publicly not treating this situation as what it is.