You practically proved his point. It doesn't matter whether fundamentalism is risky, it's not a practical threat and therefore is not anything to be afraid. Destabilizing influence? Give me examples. Historians have no phobia of fundamentalism because it doesn't matter in today's society.
There is an incredibly fractional chance that Sharia will take hold. That's what the OP was saying.
It's already taken hold in countries spanning a very large number of people. It matters in Pakistan for example. Pakistan has nukes. There's a threat there to everyone.
Sorry, I suppose I wasn't very clear. I was referring to the fear some people have of Sharia law taking hold in the U.S., not in other countries, which is a baseless fear that can be used by those in power to manipulate those who are afraid. The fear of fundamentalism in other countries is not so baseless, but it can still be used to manipulate people if those people don't examine the relationship between their fears and the policies advocated in their name (ie. fear of fundamentalism justifying not just surveillance of fundamentalists but of everybody).
Your use of the word "practically" is very generous. I'm not sure I could have proved my point better if I had created a fake account to reply to myself saying exactly the right things to prove my point.
There is an incredibly fractional chance that Sharia will take hold. That's what the OP was saying.
It's not a real threat.