If anyone was familiar with the Church's aggressive attacks on its critics, you'd know why Anonymous wears masks. I suggest you read up on the framing of Paulette Cooper and Operation Freakout.
http://home.snafu.de/tilman/krasel/cooper/
Her personal account (much more detailed):
http://www.lermanet.com/paulette-cooper/
It's not about being against their beliefs, but being against their methods. They're some bizarre mixture of a cult and business that suckers in weak minded people, drains them of all their money and turns them against everyone, including their families. That's not even mentioning their ties to criminal activity such as Operation Snow White (infiltrating government agencies to destroy documents) or the mysterious deaths/suicides of its critics. Anonymous isn't trying to destroy them, but rather get rid of their tax exempt status and expose their cult-like tactics.
