That's it!!
the vast majority of religions that claim to be Christian in the world is a mixture of the Mosaic laws and some parts of the gospel of Jesus

Moralty implies benevolence and charity, if that's what YOUR OWN PERSONAL moralty defines. A high moralty involves thinking about society's profit, but it doesn't mean you stip being free.
Check that twice if you need

This concept of morality has become subjective in our dialogue.
I believe it is because of the ethnic difference.
Morality I know is the right conduct of human beings.
I will summarize, do unto others as you would have to do with you.
I am wrong?

Not 100% right either. For instance, I provide to others, no matter how they treat me back. Moralty regards to the highest standard, not really expecting to get anything back. But yes, it does imply the most righteous human behavior possible.

I guess moralty doesn't restrain anyones freedom to decide what to do, like believing in God. Or not.

you are exactly right !!
an example in my family:
I have a nephew who is atheist.
He is extremely intelligent, fair, honest and good-hearted.
this is an example of morality, however to achieve relative perfection of morality, we must go far beyond these examples.
Only through charity (material or not) and the constant work for the good, we can achieve this sublimation.

Then you will Quite agree that if you as a Christian believe in a god ( or the god) you cannot believe that there is no God at the same point in time?