Before answering this thread, I thought I had better check my facts. So I re-read the official UKIP policy on their website. I also read their manifestos for both the European and local elections. I can find nothing there that calls for repatriation, expulsion or anything similar. Or, for that matter, anything remotely anti-muslim.
So I can only see three possibilities.
1) I have missed some critical document which lays out such a policy or
2) That there is some hidden policy set of which you are aware, but I am not
3) That you have been made to think that UKIP has policies which in fact they don't have, by parties or individuals in whose interests it is to rubbish UKIP.
I will confess that I found an excess of material relating to immigration, and (to my mind) insufficient on what I consider to be the core issue of leaving the EU. I think that this is both a tactical and strategic mistage, and had I been asked, I would have counselled against it.