Not sure if I can agree with 'democracy' (which I believe you're using equating to the US style of representation) is a prerequisite for tolerance. The Dutch have had a monarchy that was pretty tolerant on a lot of things for a while (just as an example of it not being required). I'd be Ok with saying that democratically formed governments are more likely to be tolerant because tolerance works toward enhancing the number of votes they can get.

But your second comment is scary indeed. "transplanting our culture/values", especially when it comes to US culture and values, is an offensive thing to a lot of people in the world. The US State department pushes exactly one 'value' (and no 'culture') which is that the people who are governed have the right of electing the government they want. Period. There aren't any constraints put on the kind of government the people pick, be it heavily church influenced, strict representation, constitutional representation, etc.