The concept of religious liberty is so deeply ingrained in our American heritage that there is no way that people, including devout Christians, would accept such a law. That heritage was enshrined in the First Amendment, which prohibits Congress from enacting such a law.
Now, suppose things had been the exact opposite. Suppose that from the beginning, the Constitution had authorized Congress to enact compulsory church-attendance laws. Suppose that immediately after the Constitution called the federal government into existence, Congress had enacted a law requiring parents to send their children to church, in order to be educated on religious, moral, ethical, and Biblical principles. Suppose that we had been living with that national compulsory church-attendance law for the entire history of the United States.