How do taboo acts work in tantra if people don't see the acts as taboo?

Tantric rituals harness the power/engergy of taboo acts by including either actual or visualizations of alcohol, meat and sex into the ritual. In that system, does it still work if people don't actually believe that there is anything wrong with drinking alcohol, eating meat or sex ? Also, maybe I just am not familiar with tantra, but this list is 3 out of five of the five precepts. Do tantric rituals also harness the power of theft and killing?