Megan McArdle makes an excellent point that, if you want to argue that big business can't exist without society* and therefore society has a right to tell people how to conduct private economic transactions, then it's awfully hard to argue that society has no place telling people how to conduct private sexual relationships, given how dependent our present ideal of sexual freedom is on, at the very least, a legal system for prosecuting and punishing rapists.
It's a point leftists would do well to consider the next time they wave off moral objections to the annual crop of thousand-page regulations of every aspect of economic life, and the right the next time they figure their mandate to Defend The Family justifies their intrusion into my choice of spouses.
One interesting note from the comments section:
We also often wish to introduce steps to protect a minority, in a democracy, against a majority. And what many right wing types would say is that we need to take steps in a democracy to try to protect the majority against a well-organised minority proposing a solution that transfers a small amount of money from each taxpayer, too small for any individual taxpayer to worry about, to the members of the minority, which are small enough that the amounts they get are well worth lobbying for.
Weren't we supposed to learn when we were children that "the store won't miss it" isn't an excuse for shoplifting?
[* - And I'm not going to argue that isn't true. Our megacorporations get extraordinary benefit from manipulating and gaming federal regulations; without the mountain of well- and ill-intentioned laws creating a million opportunities for regulatory capture, I wouldn't be remotely surprised to see most of the current biggest players collapse.]