Jonathan Freedland in the Guardian has suggested that Cameron calling Calais a 'bunch of migrants' is 'beneath him'. I don't think so. I think it IS him.
It comes from his milieu. There's an 'us' who are normal, right and good. There are people who are loyal to 'us' and they are normal, right and good. They might be inferior but they're good. Then there are the 'other'. The 'other' are suspect, dangerous, surplus to requirements, and a possible or probably threat to the order that 'we' rule and run.
That's why it's a 'bunch of migrants'. If this country were bombed or invaded, Cameron might find his family were a 'bunch of migrants'. But only very rarely in history do the Camerons become the 'other'. It happens - but rarely. For now, and for the rest of his life, he'll be OK, I'm sure. He'll go on 'bunching' the 'other'.