Oppression takes a number of forms, overt and subtle. It depends upon your metric. No, you've never seen "Theists Only" bathroom signs in bus stations but it may be what you don't see that's important. Consider the religious beliefs of membes of the US Senate as an example (ref http://en.wikipedia.org/wiki/Religious_affiliation_in_the_United_States_Senate ) Atheists have zero representation. Zero is a fairly good indication in support of the OP, don't you think?
'The most basic breakdown of the above data indicates that 85% of the Senate is Christian (compared with 79.8% of the population) and 13% of the Senate is Jewish (compared with 1.4% of the population). According to the data, no Senator falls under the category "No Religion/Atheist/Agnostic"—a category embodied by 15.0% of the U.S. population according to the 2001 Census—although two are under the description "unspecified".'