As I've said before the frequent and incorrect use of the racist jibe is socialist sop to any critiscism by the indigenous UK population of multiculturalism, islamic extremism, immigration policy, foreign criminals and prisoners etc.
During the dying months of the last failed Labour Government it fell out of use somewhat as they realised they were losing supporters with Joe Public strongly feeling that mass uncontrolled immigration was wrong and that muslim extremists shouldn't be kow-towed to.