It's literally worse than nothing.

"How do we make people less extreme and more open to our culture? Oh, I know! We harass and insult them! That's sure to make them want to join us!"

Nah, fuck that. I hate religion more than most, but this isn't how you create change. You change things by making them feel accepted and a part of the culture. French isn't a thing that came from nothing. It's a conglomeration of all cultures of the people before who joined as one into a fairly cohesive group. This is true everywhere.

Muslims aren't better or worse than these groups (in fact, they're part of it already). However, anyone who thinks they are worse is worse than them. You want them to be accepting of your culture, and you can't accept any of theirs? Yeah, fuck you. Maybe you're the extremist who doesn't deserve to be accepted.

I don't "do nothing," I fundamentally disagree with your entire framing of the situation.