The radical-ness of this doesn’t stem from the moral implications, it stems from how reality-denying it is. Young people have discarded the taboo of sexual promiscuity for at least a few generations already. But you need more from relationships than just sex, which is why we have the concept of “settling down” eventually to have a long-term, committed partnership.

Sexual compulsions are very influential, but people almost universally find relationships revolving primarily around sex to be completely unfulfilling (eventually).