>Morality is not contingent on having faith or belief in deities. You can have a moral code of human ethics of how to treat and respect fellow human beings.
If there is no God, any moral code is as man-made as any deity. You can invent your own moral code, but that's like inventing your own deity.
Moral codes only matter when many people follow them. Religions throughout history have cited gods as the reason why they should be followed.
If a fellow mortal invented a moral code for others to obey, why should anyone obey it when they could just invent their own?
>Language is man made....you use it.
Atheists reject religions which are constructed by people. And you didn't choose the language you speak. Charles Tart said all people from birth are induced into the "consensus trance" of the culture around them. That goes for language, and all memes.
Humans invented language. If there is no God, it is only language that allows people to believe in God. Language, since it's abtract, allows people to talk about things that don't exist. Like blind superheroes that fight crime. Or gods. Not much difference between deities and superheroes.
If someone rejects religion as a delusion but still embraces language, language is the thing that leads to more delusions than anything else.
>The morals are usually agreed upon by most of the society to be acceptable...
What do you think religion is? A social system of morality. And if all deities are man-made, so are all "rights." You think rights exist because people say they do, but gods don't?
If someone believes in God-given rights, then no man can take them away.
>Because you live in a society with other people...
You laugh at the deity but take the law seriously? Most deities come with rules to follow. The deity gives the rules more authority than mankind. If a mob is the authority, why should you obey them?