"Atheists have better sex" is a general statement meant to be taken as a thumb rule, not as an law of nature. Giving arguments about how "some atheists have shitty sex-lives" or how "some christians have great sex" is not really relevant here.
The argument is pretty simple. Most religions demonize sex and sexual desires. Thus the stigma and shame associated with it reduce the quality of sex religious people have. Atheists, not being bound by these notions, achieve greater pleasure due to absence of guilt and/or greater interest. The conclusion makes sense. When and where these statements do not apply, e.g. religious people without guilt or atheists with, the statement is no longer true.
The argument is pretty simple. Most religions demonize sex and sexual desires. Thus the stigma and shame associated with it reduce the quality of sex religious people have. Atheists, not being bound by these notions, achieve greater pleasure due to absence of guilt and/or greater interest. The conclusion makes sense. When and where these statements do not apply, e.g. religious people without guilt or atheists with, the statement is no longer true.
