I got a pretty good laugh out of the "join hamas" story lol. There *are* ways to get into Gaza, but it's pretty difficult to do - basically if you don't have family living there (and sometimes that's even an impossibility if you don't carry the right kind of passports) unless you're from a religious organization, charity, or a journalist. It *is* possible, but it takes a lot of work. It's also not hard to join "hamas" if you can vote for them (ie be Palestinian) - I assume he meant to join the Al Qassam which is the military wing of Hamas - but they don't even have weapons or supplies for all of their own members (being as unemployment in Gaza is so high tons of people have the spare time to join a militia and march around).
The problem is certainly *not* Islam in an of itself, because most of the "bad stuff" that people point out as being present in the Qur'ran *are also* present in some form in the Old Testament (and in some cases the new if you'll review Timothy). It's simply that the whole region has had to find some outlet for its dissatisfaction. In the 30's many of the nationalist groups, or pan-Arab groups toyed with the idea of joining the Axis or sent feelers to Hitler to see if there was any potential for them to gain independence from French and British hegemony with the aid of the Axis. Of course, that route didn't turn out so well, and a lot of people got shot.
So, West Asia, and its independence movements, turned broadly left, and started to court aid from the Soviet Union, or in many cases, both sides, with aid from the Soviet Union serving to ignite fear in the West and to cause them to give aid as well in increasing quantites. Ultimately, this didn't turn out well either - because Western nations generally stepped in and had all of the more pro-Soviet elements shot to re-secure economic hegemony. But they came back, so the "West" broadly speaking, chose to back Islamic radicals *and* traditional power bases willy-nilly.
Just for some examples. Iraq had a royal family, they were exceedingly corrupt and were overthrown by a series of military governments who purported to be broadly "Marxist" in approach, we fixed that problem by backing the "socialist" ba'ath party of Saddam Hussein. He was wildly popular and the US is still rightly regarded as having made an excellent decision here.
The US didn't like Nasser in Egypt because he was heavily courting aid from the USSR, so initially we backed Islamic "radicals" called the muslim brotherhood to get rid of him, but eventually he died of his own accord, and the guy after him ended up being a little bit more pro-US, and then he was shot by our *original* friends the Muslim Brotherhood and replaced by an exclusively pro-US guy Mubarak, our support for whom still makes us incredibly popular and well liked in the region. He was generally considered a great guy.
Afghanistan was once one of the most progressive countries in the whole of Western Asia, women didn't wear traditional "religious" head-gear, held prominent positions in government, and several government initiatives had aimed to make Afghanistan a viable agricultural exporter by constructing one of the largest dams and irrigation works in the region. But they were just a bit too far left, and when "radicals" started to rebel against the progressive policies of the government, who outwardly declared that it was Communist and pro-Soviet. The US chose to back this organization, I don't know if you've heard of it, called Al-Queda, lead by a really nice guy called Osama Bin Laden. Luckily for us, he won, and the Soviets chose to withdraw. Then that big farm project was switched over to opium production to make *real* money too, so it was really a win win for everybody involved, and we're still hugely popular for this decision, because like I said, they were such great guys who also happened to love freedom.
Basically *any* country you pick in the whole of Western Asia has a narrative that could loosely fit this form, but I'll present those cases alone with a heavy dose of sarcasm to help get my point across.
The point is, the reason "Islam" is so bound up with "terrorism" that is to say that those who feel that the best political tactics they have in hand are terroristic ones, tend to use Islam as a justification for those tactics, is because everybody else who mayhaps wouldn't have used Islam as a justification for their political acts, have already been killed, and their organizations completely destroyed. There simply are no organized liberals, or socialists, or social-democrats, their organizations have all been shattered time and again, and the only groups that are sufficiently organized to carry out political actions with clear goals in mind, are the radical religious groups that the "West' made such a habit of backing for years and years.
I also wouldn't be inclined to jump to conclusions about going to Turkey - of course the US government will because they're incredibly afraid that somebody would come back from there with ill intentions, but he could also have been meaning to join the US backed FSA or one of its subsidiaries, which does take foreign fighters, or perhaps the PKK (Communist Party of Kurdistan) who also takes foreign volunteers (a group of German bikers recently joined them and they've been blogging about their experiences lol) or the Kurdish Democratic Party (the nominal governing party of the Kurdish Regional Government) who also takes on foreign fighters. Or maybe he just really wanted to smoke some shisha and look at some old buildings like most people who go to Turkey before this all started lol.