When we were colonists and fought a war against the king and Parliament so that we could secede from the British Empire and be independent of it, we also fought for the value of personal freedom. That is the idea that in matters of personal choice, the government should play no role. The king only cared about the colonists' personal choices if he could control or tax them.
One of the taxes he imposed was to support the Church of England. The Church of England that the colonists' tax dollars supported was, of course, in England; it was not here. So, among the hateful taxes that impelled the colonists to revolt was this tax to support the king's church.
When the Constitution was written, religious freedom was a principal matter for discussion and debate among the Framers. They addressed this in the first clause of the First Amendment. Before the Constitution even protects the freedom of speech, it protects the natural right to worship or not to worship, free from the government. Here is what it says: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..."
That is very direct and clear. It was intended to prevent any tax money from going to a church, and it was intended to keep the government from using its coercive powers to influence or to punish religious institutions. For 125 years, most governments in America left churches alone.
Then along came the progressive attitude that some ethnic groups are superior to others. This is a damnable and racist view that was foist upon the federal government by Theodore Roosevelt and Woodrow Wilson, in direct response to the influx of southern European immigrants at the beginning of the last century, most of whom were Catholic. Roosevelt and Wilson and their progressive followers thought these immigrants had too many children, children who would grow up to be voters and vote out their Nanny State central-planning values. So they began to encourage birth control and sterilizations and even abortions.
The Catholic Church resisted this by its teachings on birth control. The Church had made its teaching on contraception a core part of its mission for 400 years, and Pope Paul VI reaffirmed these teachings in a permanent way in 1967. That the Church embraces these teachings is well known, and equally as well known is the policy of the federal government to resist them.