By even acknowledging that the decision in 1953 was not the "wisest", you've completely disproven your argument that there's something about Arabia which means that democracy can't function. It has functioned, but it has been the West and Israel which has supported brutal dictators and kept them in total control of their countries. Incidentally, you understate the situation - it wasn't the wisest, it was an imperialist crime perpetrated by the United States and its junior partner, Britain.
And, today too, democracy is functioning, namely in Tunisia: it shows what can happen when the West is not interfering and when one of the West's corrupt totalitarians is overthrown by the people.
The 1979 revolution consisted not just of conservative Islamists, but of people from many different backgrounds and with many different views. The disgusting tyranny of the Shah, supported by Britain and the United States, proves only one thing: you're putting your faith in the wrong countries if you claim to support democracy. You're simply an apologist for revolting totalitarian regimes when it suits you.
Why don't we occupy and annex all the Arab countries seeing as they don't have democracy? The answer is simple - we, including Israel, support the totalitarian regimes. This has nothing to do with democracy, and everything to do with colonialism.