If there is no God and thus, no afterlife, you just live and you die, you certainly would be dum
Without God, morality is self-defined.
Why is that bad thing?
I am more than capable of coming up with my own morality.
Relationships are based on trust and so betraying that trust would be immoral hence I value the trust enough to be moral. I don't need your imaginary being to dictate that morality since I was more than capable of figuring it out for myself.
Ever notice how those who want government to butt out of their lives are more than willing to force their religion into the lives of others, by force of government if needs be?
So no, your imaginary god does not define my morality.
If there is no God and morality is self-defined, there is chaos. Do you think everyone is going to have the same moral code? Probably not.
Also, people don't have control of other people.
God has control. But people just don't like to hear that.
Who is forcing their religion on others? People will strong convictions are going to stand by them, it's called commitment. And demanding to be heard is a right all people have. Even Christians.