“Progressive Islam” is not going to destroy the religion any more than any other radical reinterpretation, such as the Jihadis or Khalifahists, or what have you. Some people will follow fringe ideas to suit their whims and inclinations, some will even get financial and political support…but ultimately, none of these things last.
I am not saying don’t take misrepresentations of the religion seriously, just don’t exaggerate. We have a long history, and there are plenty of examples of whacky groups springing up with unorthodox views, and they will keep springing up in the future. When we get deep into polemics, we tend to inflate the significance of this sort of thing, and act like Islam itself is hanging in the balance…it isn’t. Islam as we have always known it is not going away; the practices and opinions of the people will ebb and flow from generation to generation, but everything is going to be fine.