wow i'm glad i stumbled upon this question. Would you like to be a trafic warden? no. so who does it? all the migrant workers. have you ever worked on a checkout? i have- it was the most soul destroying and badly paid job i've ever done so would i ever do it again? no.
Migrant workers fill in for the service jobs that 'british' people dont want to do because the job is either awful or the pay is awful. The point i think the government is trying to make is that this job divide between brits and migrants is not productive for a coercive society where we all love and respect each other as equals (no im not on acid).