The issue of asylum seekers is not a vote winner: in fact, the complete opposite. But they can hardly be abandoned, especially those who are unaccompanied minors, so they fall into the political ‘too difficult' box.
Ministers want to sound tough, the public isn't interested, so the onus falls on the local authority which just happens – by an accident of geography, a port or an airport – to have to take responsibility for housing minors.