Why did mormon, catholic, and jewish americans face discrimination?

The Mormon, Catholic, and Jewish faced discrimination from the Americans because they were not Protestant Christians. The Americans were Protestant Christians and so they looked down upon all other community other the Protestants. This was the only and the major reason behind such discrimination. It was not limited to the Mormon, Catholic, and Jewish but the discrimination was there against the Muslims and the Hindus as well. Americans are still a dominant force around the world, but the discrimination is still in existence.