If you really believe that all sexual activity between consenting adults should be legally permitted, you ought to object to laws against incest (when no child is involved) and polygamy too. (The adultery example doesn’t really fit, since adultery involves a usually nonconsenting third party, the betrayed spouse.)
The real point here is that except for a few radical libertarians, hardly anyone actually accepts the principle that the government must never regulate private, consensual sexual behavior. What regulations one finds acceptable or desirable is a matter of custom and tradition as much as principle. And custom and tradition are subject to change. [James Taranto, “Best of the Web Today,” 4/23/03]
See? There’s no principle at all here; it’s all abject second handedness. What’s actually right or wrong, or what the facts are, is not important; just follow custom and tradition–i.e., what other people think. (The ad hominem shows only that he has no case of his own: as if sneering about “radical libertarians” or their alleged small numbers is at all relevant to the truth or falsity of the position he’s criticizing.)
We have the Founding Fathers to thank for the fact that America was founded on the rejection of custom and tradition, and that it protected individuals’ ownership of their own lives from the kind of morally empty majoritarianism Taranto is espousing here.