Mormons leave because they find out the truth about mormonism...
and they find out they have been lied to...
And Catholics leave because they find out that some sodomite priest buggered their little boy. And Presbyterians (USA) leave because communists have taken over their church leadership. AGs leave because of the unwavering demands of tithing. Baptists leave because they want to dance. Snake handlers leave because they get bit and die. And Methodists leave because the bank has repo’d their church.
It’s called life. Deal with it...