Merkel had nothing to do with this development as the UK never took substantially more refugees than in any other years. She made the right decision to help people in need, it was only the execution which lacked.
She only helped the richest immigrants - those represented the overwhelming majority who were able to make it to the EU because the fees of the human smugglers were in the thousands or tens of thousands of Euro. The millions of people who are in much greater need are still stuck in horrible conditions in refugee camps in Turkey, Jordan, etc., etc.
This is a very complex issue and I could not help but to respond to your over-simplifying comment.