I haven't seen or read a thing about bums, homeless or vagrants in anything that I can find concerning this incident.
From everything that I have seen it sounds like a customer felt unsafe due to the presence of other customers. The Barista was put in a tough position, and tried to handle it as best they could.
In today's society, one side (the police and it's supporters) or the other (those that feel unsafe in the presence of police) was going to be up in arms about this. Looks like your arms in the air this time.
This isn't corporate policy, Starbucks has apologized repeatedly for this occurrence... they also closed 8000+ stores last year for sensitivity training due to another occurrence. What more do you want from them?