Yeah, I took a look at the website - it's very easy to pick apart. Among other things, surely you've noticed that if "stealth Jihadi" Muslims really wanted to, they could just move in to some empty county of Michigan or similar and simply vote Sharia Law in - completely legal, completely Constitutional. If there are so many of them, then why hasn't that happened yet?
As for why they're being forced out of their country, I don't know what you're expecting from these guys: if they stay home and fight, they get slaughtered by either Assad or ISIS, neither of whom have ridiculous insane numbers but Syria is mostly desert. It's very difficult at the best of times to form stable societies in remote areas like that, never mind when you're caught in the middle of an all-out war between two sides neither of whom you support and both of whom want to slaughter your town. Think of the desserts of Mexico, or the jungles of Burma - doesn't take a lot of troops to create death and destruction in those areas. What do you want these guys to do? Stay and get a face full of chemical weapons? If I were in their shoes, I'd say "to hell with this, we gotta leave" too - I'm not defending my village against 200,000 soldiers.