How has it got to this?

[The Lone Gunman]

Ok. But they are police. Is that an excuse for this sort of behaviour?

Your heading says "how has it got to this?" as if the notion of a group of policemen backing away from a rowdy bunch of thugs is a new development.

All I can imagine is you haven't been to many City away games over the years if you've never witnessed this sort of behaviour before.