>>17264008America is cool with the Sauds because they acknowledge that they are reasonably speaking the best option Saudi Arabia has at the moment and that any attempt to destabilise the regime would result in worse outcomes from every possible perspective. The Saudi people are extremely socially conservative and the the government is vastly more relaxed, so the Sauds are considered the most reasonable people in the room.
Incidentally, yes, Iran is significantly more Islamist in terms of government than Saudi Arabia despite having a population as secular as Eastern Europe. Going after the Iranian government, one that says 'Death to America' in every session, is perfectly reasonable as it's highly likely a more reasonable government would take its place if the country was democratic.
