Power’s tendency to corrupt is a function of the work it does in liberating man’s worse characteristics. - A. C. Grayling

Aristotle’s thought is that to live well and flourishingly, a person needs to be educated—which means: informed, and able to think. He is of course right.

Tolerance is not only a key feature of liberalism, but—familiarly—its paradox too. Liberalism’s tolerance leaves the democracy of ideas to decide which among opposing viewpoints will prevail. The risk is the death of liberty itself, because those who live by hard and uncompromising views in political, moral and religious respects always, if given half a chance, silence liberals because liberalism, by its nature, threatens the hegemony they seek to impose.

Most moralists, and certainly all those of a religious persuasion, think that pupils should be “taught values” at school, not mainly so that they can apply them in thinking about the implications of science, history and other subjects, but to make them behave in ways that they (the moralists) find acceptable.
But the point of equipping people to think about ethics is not to impose some partisan set of principles upon them, but to develop their powers of reflection, and to inform them of possibilities and options so that they can think for themselves.