When the Republicans in Congress impeached Bill Clinton, they said the case was not about sex but about lying. Everyone knew this was bull; they impeached him for lying about sex, but ignored everything else he lied about (or at least that they believed he had lied about; actually the testimony they used to impeach him was the testimony in which he told the truth about how he evaded the inept questions of the laywers in the Paula Jones case). So, in short, it was still about the sex because the Republicans only cared about lying when it was lying about sex.
The same thing is true now. Republicans in Congress are universally claiming that their attempts to allow any employer to opt out of allowing their women employees to have free contraceptive coverage are about religious freedom. The problem is that religious freedom only became an issue when it was about their religious freedom to deny contraceptive coverage to women employees. So, leaving aside all the other absurdities in the religious freedom argument, the debate is not really about religious freedom when the so-called religious freedom only concerns sex.