Is it true that there is no absolute morality?

[WisdomOfTheTrees]

Call it arbitrary if you wish but I can pick and choose from any "objective" religious moral lesson. I think the fable of the Good Samaritan is a good moral tale. Rise above the bigotry of your culture and help a human being who is in trouble. I think human sacrifice and killing your own son for the bad behavior of others is sick. My moral landscape has been shaped by more than iron age tales of brutality.

If one defined morality, then there would be nothing of which to disagree on, there would be nothing to deviate from. Since there is no defined morality, that means whatever one chooses to believe is morality is arbitrary.