I doubt somewhat that a radicalized Muslim would be any more or less tolerant than a dedicated JW. Or, for that matter, a really hardcore fundamentalist protestant christian. Many religions are in fact quite intolerant of others.
I suppose, though, that with the current political climate - such an intolerant Muslim would probably be less likely than a JW to actually admit to the intolerance. It is almost a Mantra with them to assure everybody how peace-loving Islam really is, all the while they are preaching the evils of the west.
Whereas, of course, the JW is trained to be proud of their intolerance, as if it were a badge of honor. They are required to show this intolerance in public - as per flag salute, national anthem, preaching the destruction of everyone else from door to door, making fun of non-witness holidays, etc.