I was careless! I admit it. Rationality can't lead to morality. What I meant was that rationality can be used with any morality, and as such can lead to any outcome (including killing off millions of innocent people). You are on the wrong track if you believe morality can be derived from rationality.
Beliefs belong in church, they have nothing to do with rational thought.
Regarding your admitted carelessness, welcome to the real world.
Part of Ayn Rand's brilliance is that she continually checked her premises. In so doing, she used her mind to check on her mental processes, a self-exam far superior to Christians checking their consciences over adherence to things like man-made religious rules. Checking her premises was also a habit that resulted in her writing with incredible clarity -- always.
Killing off millions of people is not the result of a rational ethics, it is the result of the ethics of altruism -- the ethics of communism, socialism and Christianlty; where self-sacrifice is not optionsl to the individual, but mandatory. Tithing is a minor example. And those Russian/Nazi massacres you mention are the product of altruism, too -- massacres that were "justified" (in Stalin and Hitler like minds) for the good of the state.
Checking one's premises can lead to startling observations.