To the contrary. Those words are never mentioned in the Constitution, nor can you find them. It simply states, Congress will make no law respecting an establishment of religion. That does not mean what you believe it does. You clearly missed the second part where the government cannot interfere with the Free Exercise Clause. It's still debated to this very day regarding schools, particularly, private religious schools.
Why do private schools have the right to teach a certain religion, and not others?
Like I stated earlier, I don't agree with Texas, but it's definitely a gray area, and will likely go to the SCOTUS. That said, look at Jefferson's letter to the Danbury Baptists in 1802.
"Believing with you that religion is a matter which lies solely between man and his God... thus building a wall of separation between Church & State."
The SCOTUS used his words to reinforce the Establishment Clause in the 20th century.