An idolater is one who worships a false God. Last Sunday was Super Bowl Sunday. Our values come clear when the value is worship vs. football. We're called to be worshippers of God, not idolaters. There was a movement beginning in some of the churches of the Greek empire that treated sexual immorality as a light thing.
Scholars call it proto-gnosticism.
The body is matter and therefore bad by definition, these people would teach. The spirit is good and holy. In a darkening world, Christian purity and faithfulness shine all the brighter. Whereas in the 50s, America espoused these values culturally, in the late 90s purity and goodness are mocked and caricatured. It's hard for us to stand against our culture, to be counter- cultural.