Here is the great divide between those who are left of center, and those center and right. It's not so much about favorite 'moral values' [as is being batted about now], but rather more about the foundation of morality: is it based in transcendence [i.e. God and revelation] or in human constructs [i.e. self and society]? Is it objective in origin, or subjective?
It is an age old argument that Socrates [via Plato] argued against the sophists. The sophists claimed that 'man was the measure' of all morality [i.e. subjective, temporal], but Socrates argued that something beyond mere self was the basis of moral action. Nietzsche railed against Christians [and Jews] for following Plato and denying the sophists. Nietzsche bitterly asserted that through Christianity, the Jews [and Socrates] had won. Jews and Christians, against the whole world, claimed that morality was based in relation to the Absolute, the One God.
The argument will continue until the end of time. But it is important to understand the distinctions in it.
Jonah Goldberg tells it well:
What Maher [and leftists] fail to grasp is that all morality is based upon transcendence — or it is merely based on utilitarianism of one kind or another, and therefore it is not morality so much as, at best, an enlightened expediency or will-to-power. It is no more rational to vote based on a desire to do "good" than it is to vote based on a desire to do God's will.
Love, in fact, is just as silly and superstitious a concept as God (and for those who believe God is Love, this too is a distinction without a difference). Chesterton's observation that the purely rational man will not marry is just as correct today, because science has done far more damage to the ideal of love than it has done to the notion of an awesome God beyond our ken. Genes, hormones, instincts, evolution: These are the cause for the effect of love in the purely rational man's textbook. But Maher would get few applause lines from his audience of sophisticated yokels if he mocked love as a silly superstition. This is, in part, because the crowd he plays to likes the idea of love while it dislikes the idea of God; and in part because these people feel love, so they think it exists. But such is the extent of their solipsism and narcissism that they not only reject the existence of God but go so far as to mock those who do not, simply because they don't feel Him themselves. And, alas, in elite America, feelings are the only recognized foundation of metaphysics.
This line of thinking is worth considering, and understanding.