People need structure for life and for the most part, religion has fulfilled that role. As long as they keep it private I wouldn't mind. However I think the secular state should pursue those that use religion for harm (pedophile clerics, extremists inciting violence) and not let them hide behind "separation of Church and State".
It's kind of confusing sometimes since there are several interpretations of islam's teachings. Some moderate muslim can really convince you that islam is not about jihad and hate towards non-believers. I've come across some of these muslims and they're one of the most tolerant group of people i've ever encountered. And then there are the extremists who, as well all know, take the teachings of the Quran way too literally without giving ground.
Meh, wouldn't trust even "moderates" with the whole taqqiya thing floating about. You can never really be sure if they are telling you the truth when you ask them anything related to their religion.