Yes, sex and love should walk hand in hand, but unfortunately, they usually don't. In fact, the very type of sex that Johnson advocates is completely void of any love at all.
Sex can be an expression of love or an expression of selfish lust.
STD's, or even commitment enters the picture. I would like to propose that sex can indeed be a beautiful expression of love when it is used within the context for which it was created. The Bible is clear that the very God that created sexual beings, as well as sex itself, has the wisdom to know how this blessing can best be cherished and enjoyed. Rather, He is commanding us to live in a way that will glorify Him and satisfy us. By trying to grab fulfillment everywhere, we find it nowhere.