Well, you could have just stuck to answering the question posed by the OP, with an open mind of course.
What rudebwoy has done is challenge the use of a culturally derogatory, insulting and divisive term used to describe a particular social group the media has ‘identified’ as an ‘underclass’. I see nothing wrong with that. I also dislike the term as it’s invariably used in a negative manner, and betrays the prejuidce and resentment sadly inherent in our society.
Other equally offensive and prejudicial terms have at one tme or another been socially acceptable, but following challenge to their use and intent, have thankfully become unnaceptable.
Personally, I don’t see the use of words like ‘chav’ to be fundamentally any different to other offensive names for certain minority groups; the user is still identifiying a person according to stereotypes and prejudiced ideas, rather than as an individual.
The OP could have simply said the window was smashed by idiots, thugs or hooligans, without making any refererence tot he social background of the perpetrators, who, as yet are actually unidentifiued.
And we wouldn’t be having this discussion.