That will just shift the job of who will have to kill them, to the Muslim regimes. The refugees will know this. Any attempt to repatriate will result in civil war in Europe, and armed conflict with the Muslim countries that will resist repatriation.
Don’t give them a chance. Arrest, shove onto a gangplank, onto a ship. Send the ship to a destination only known to the captain, and keep some muscle on the crew in case they decide to revolt on board. The Muslim regimes won’t like you anymore? They’ll decide to do the mass killings, though. Germany has done too much of that, and a penitent must avoid temptation. As for the British, they’ll agree that that sort of thing simply isn’t done, stiffen their upper lips, and get ‘em on the ships. The French? Poetic justice. We follow the Germans’ example. Hon hon.