The Constitution is about protecting the minority from the tyranny of the majority. That includes faiths. A faith cannot be promoted by the government just because it's the majority faith.
Perhaps you'd have no problem with a predominantly Muslim municipality promoting Islam as the "true faith" over Christianity?
No that is not what the Constitution is about. It is about establishing legitimate roles for the government, and the first ten Amendments were about protecting the rights of people and states from the power of the government. Whether someone says a prayer at a graduation ceremony should be of no concern to the government.
A faith cannot be promoted by the government just because it's the majority faith.
Promoting faith? I just want the government to respect the will of the people as long as it does not actually infringe on rights of individuals. No where in the Constitution does it say people can not be exposed to other people religion. Quite to the contrary, it says the opposite, people have freedom to express their religion.
Perhaps you'd have no problem with a predominantly Muslim municipality promoting Islam as the "true faith" over Christianity?
I have no problem with them expressing their religion. Attacking someone else's religion is not appropriate.