Atheism and morality

[Inigo]

A moral belief is a belief such as that 'Xing is wrong' or 'Xing is right'. To believe an act is wrong is one and the same as believing it to be immoral. That's a moral belief.

Why do you put the word belief where I bolded?
Why not "consider"? or "define"?

To define an act as wrong is... what morals are...?
To consider an act as wrong is... what morals are... ?

To establish that the consequences of an act are detrimental to society, or just the other person, is what it means to be wrong.

So... I keep spinning my marbles, but belief is a word that still doesn't make sense in this context.

Why do you start everything with it?

I was clarifying that 'wrong' and 'immoral' are synonyms as are 'right' (in its moral sense) and 'moral'. This was to clarify that a 'moral belief' - which you, or someone, was professing difficulty understanding - would include things such as a belief that an act is wrong, or a belief that an act is right.

Now, moral beliefs - that is to say, beliefs about what is right or wrong - are distinct from the rightness or wrongness.
Anyone who thinks they are analysing 'morality' when they start giving an account of how it has come to pass that we have moral beliefs, is doing no such thing. They are guilty of having mistaken moral beliefs, for the thing believed. They are making a mistake of exactly the same kind as when someone mistakes a belief about an apple for an apple.
Now, if someone persists in mistaking beliefs about apples for actual apples we would - at a certain point - conclude that the person is so hopelessly conceptually confused that further debate with that person was pointless. We are close to getting to this point where moral beliefs are concerned. If someone really can't grasp - or just plain doesn't want to grasp - that morality and moral beliefs are distinct, then there is no point continuing discussion with that person. And that person is certainly not entitled to believe that they have in any way 'refuted' or 'blown a hole in' my argument. They have not even grasped the meaning of the premises. Failing to understand an argument - failing to grasp the meaning of its premises - is not the same as refuting an argument. You can't refute an argument by being stupid enough not to understand it.