Silly me. To start with, the issues are more complex than I imagined. The Los Feliz Ledger reported that one of the groups locked out was the Los Feliz Neighborhood Council, which is an arm of the Los Angeles municipal government, and municipal property had been in the community room. The city functionaries are no longer able to access this city property. (This is simply a pattern the squatters have already followed in the church building next door.)
Second, my understanding is that the interior of the bank building had been trashed, something observed by the city functionaries when they first entered the building on the afternoon of November 17. The locks, as reported in the Ledger, were changed after this first entry, in which I'm now told the trashing was observed. The information I've been given is that the trashing must have taken place subsequent to the end of the bank's tenancy (and a major institution like Citibank has good reason to leave such property in good condition). It is not entirely clear whether city property was also damaged.
There's a lot apparently going on behind the scenes that is as yet confidential, and I know as little as you do. However, what I know here is enough to convince me that imputing rational, adult, or perhaps even lawful motives to the squatter group is a mistake.
As of this morning, their Christmas Midnight Mass is still scheduled for August 16.