By this, I mean that the nation feels it is able to condemn oppressive regimes, even going as far as invading them, with the claim that it is done to spread the democratic ideal.

I agree that democracy is, basically, mob rule, however it remains the government system of choice for most of the world. Some countries (such as Sweden) which rate quite highly on democratic indexes seem to avoid the issues normally associated with mob rule. How they achieve this “enlightened” state is the topic of another post on another day.

There is no form of government in which human rights are guaranteed.

There is a big difference but I agreee with you that torture is bad because it violates the human rights, in a democracy no one has their human rights guaranteed, it is mere mob rule.