Cofty how can an atheist have an objective morality, on what basis?
Some things promote the well being of conscious creatures - other things have the opposite effect. This is true regardless of the opinion of the individuals involved in the situation.
For example the Taliban think it is a moral good to prevent women from getting an education and to make an example of those who disobey by throwing battery acid in their eyes. For a less extreme example they also think it is a moral good to make 50% of the population live in a black sack. Jews think it is an absolute moral good to mutilate the genetalia of little boys. Some christians think it is an absolute moral good to turn a gay couple away from their boarding house because of their sexuality.
A relativist may say that we can never confidently judge such behaviour as bad. It is relative to their culture and beliefs.
I disagree. All of these things are objectively wrong. Not wrong as a matter of opinion but wrong because it is an objective fact that these are actions that negatively impact on well being.
Many christian apologists argue that the choice is between absolute morality or mere personal opinion. This is the error William Lane Craig makes when he argues this topic.
Just as some things objectively do contribute to health whether or not an individual agrees so too some things are objectively good. There is no "absolute" standard of health but that does negate the field of medicine.
You can get an "ought from an is".