That you believe the bolded text merely shows how lacking in imagination you are.
Participating in close, loving relationships feels a lot better and is ultimately far more rewarding than living a life with no close connections. Being a part of a large community feels a lot better than being a loner. So if my purpose is to live the most enjoyable life possible, there are powerful motivators to engage in behaviors that foster close personal relationships and strong community bonds. That almost always means treating others with love and respect and creating strong public institutions.
You seem to be incapable of understanding that what is "moral" is what leads to the furtherance of "the good life." One doesn't need an invisible superbeing to understand that when I treat that beautiful young woman well, she starts treating me well in return. Her smiles are all I need to show me what is "right" and what is "wrong." Similarly, I prosper financially when I treat customers well, and I don't need God to show me that when I don't short-change my customers or provide them with inferior products, they continue to patronize my business.
People like you are so brainwashed by fantasies of immortality that you are unable to see that what is moral is right in front of your face. God need not apply.