I wonder if members of the mob weren't coached specifically not to attempt forced entry to the home?
A homeowner who opens fire on a mob for trampling his petunias will be crucified by the media - and it wouldn't surprise me one bit if some of the orgainzers were hoping such a thing would happen - they could use it to further inflame passions.
BUT . . . a homeowner who shoots any number of home invaders will be a very poor cause célèbre for the SEIU and the Washington, D.C. police department escorting them.
As unpredictable as a mob can be, I really don't see them pressing forward a decisive attack if their leaders are being stacked up in the doorway of a home they just forced entry to; they're not troops trained to face gunfire, they're a rabble. Consider Koreatown during the Rodney King riots - the mob dispersed, going on to easier pickings, after only a few shots were fired.
Hopefully, someone with a lick of common sense will see that continuing this sort of thing will not end well.