Is Benedict Cumberbatch right that posh-bashing has gone too far?

Sherlock's Benedict Cumberbatch has said that 'all the posh-bashing that goes on' made him consider leaving Britain to go to the US. He added that he was often 'castigated as a moaning, rich, public-school bastard'. Is Cumberbatch right – has posh-bashing gone too far?