Steven Taylor thinks he hurt himself:

Romney actually reinforced some of the prevalent criticisms of Mormonism, notably that it is ultimately too secretive (or, at least, very evasive) about its core doctrines when he suggests in the quote above that he basically doesn't have to go into a detailed explanation of his church's distinctive doctrines.

Larison quibbles with the "religious test" reference:

The religious tests to which the Constitution refers were tests imposed through law to screen for dissenters from a formally established, official doctrine.  You cannot have a religious test without a legally established church or religion to serve as the standard for that test.

Matt questions Romney's crude notion that all faiths agree on the basics:

Most major religions do espouse a mostly-admirable moral creed. But old-style Mormon teaching on "the evil children of Laman and Lemuel" isn't admirable. Arresting people for naming a teddy bear "Mohammed" isn't admirable. Settlers who believe the entire West Bank is God's gift to the Jewish people aren't admirable.

Hayes believes the emotional timbre of Romney's performance will help him get past the plastic problem.