Wrong - atheists do care and have struck out at religious institutions for quite some time.  One of the biggest groups is American Atheists, a nonprofit non-taxpaying organization founded in 1963 by Madalyn Murray O'Hair.  Odd that you have no use for religion in a nation founded by Puritans seeking religious freedom and in a nation that expressively protects religious freedom.  Also odd that you want to tax churches but not tax-free  atheist groups.