This is not true. If Organized Religion (OR)is a practice whose aim is to privilege its interpretation of reality and to offer an illusory, eternally deferred spiritual cohesion, there's nothing about it that challenges Capitalism -- and in fact it never has challenged capitalism historically. Rather what OR does is to provide a plane upon which this cohesion exists -- while you spend the rest of your life being a slave/master, a wage slave, what have you. Xtianity did not oppose slavery, nor does it today oppose exploitation.
While capitalism dissoves all familial and social bonds, OR remains to tie up the loose ends, by offering that "opium" Marx mentions. The resurgence of fundamentalist strains in reaction to the destructive effects of capitalism/modernization is proof enough.
Joanna