Well, the USian mindset tends to scoff at radical anything because they either can't conceive of them being effective, they have a reason to make those radicals look bad, or the idea of radicalism for them are the ridiculous and gross antics of the most non-threatening, ineffective group (that will get all the media attention they could ever want.)

There's that or they're really anti-USian terrorists in disguise. Not much room for radical opinions to exist, really.

But yes, there's a lot that happens in Five-0 that would never happen at all in real life.