Is Christian Morality Objective?

Christian apologists usually mention that morality is objective and it comes from God. I usually retort in a manner that many atheists use:

• If there were no sentient beings, there would be no need for morality.
• Even if there was a God (there is no evidence for any god, and Christianity's foundation is falsified), your God is a person (or 3 of them; that's a discussion for another time), thus, its opinion would be subjective.
• Morality is subjective. It is formed from each rational person's opinion through evolution/biology and socialization, with the input of objective information from science. In democratic societies, laws are reflective of the majority's opinion on morality. It is "bottom-up" instead of an unjustified autocratic "top-down."

If Christian morality was truly objective and came from an all-knowing, all-powerful, and all-loving God, why can't Christians and their denominations agree on what are moral acts? A good example of this inconsistency is how Christians argue over abortion:

• It is always wrong because of the sanctity of life, which begins at the moment of conception.
• It is permitted in some circumstances such as protecting the lives of pregnant women.
• It is always permitted because of the sanctity of bodily autonomy.

This link gives more information regarding the value of secular morality.