Firstly I am surprised that any question using the M word has been allowed to stay on the site for so long.
I think that until Muslims can resolve what interpretation of their holy book is the right one, perhaps they should hold back on trying to shove it and it's varied requirements onto anyone else, after all the wearing of the Niqab divides their own followers, so how the hell do we get to understand it.
More importantly, we should expect that anyone coming to a non Muslim Country should respect the law of that land, however alien it may be to their culture. We respect the right of anyone to worship their god and we even facilitate it, but we also see what happens to people from this Country when they go to an Islamic state, and break one of that Nations rules.
Muslims certainly seem to want their cake and eat it so to speak. There seems little willingness to even consider the rules of any Country, an almost arrogant belief that their own rule is all that matters and this is of course very destructive.
Back to your question, I think that many Muslims just want the right to worship their God in peace, but that a very large number consider Islam to be the only way, and have gone, will go to any length to achieve what they want.