It seems to me that it is not in the interest of sexual liberty -- or rather liberty in general -- to argue that we should be free to do X -- e.g., BDSM -- because X is good for the individual who does it or the society that allows it. In principle, liberty, pleasure, democracy, etc. are good in themselves, whether or not their short-term results are good or bad for individuals or society that puts them into practice, whether or not they make no short-term difference whatsoever to either.
If the argument is that X -- e.g. BDSM -- should be allowed because it has a socially redeeming virtue -- e.g., it is as egalitarian as or perhaps even more egalitarian than vanilla sex -- I'm afraid it concedes too much to the very sort of philosophy that has often guided state socialism and sometimes resulted in persecution of queers, prostitutes, and others, limitations on women's control over their reproductive powers, and so on. Socialism ought to be big enough to contain not only liberties and pleasures that may not have any socially redeeming virtues but also some of those that may in fact harm individuals or society in the short run. For instance, women ought to have the right and liberty to abortion even if society in which they live sees a big rise in emigration, a rapid decrease in birth rate, and/or a rapid increase in death rate, so much so that it suffers from an acute labor shortage. In such a society, abortion does no short-term good to society and may in fact be socially negative in the short run, but still the right to abortion should be an inalienable right of women.
Sometimes, costs of freedom may be dear. While in many cases protection of civil liberties go hand in hand with prevention of terrorism, sometimes it may not. Then, we have a choice to make: do we defend liberty at the cost of diminished safety or do we buy safety at the cost of diminished liberty? The defense of liberty, in the end, rests on people's willingness to say that, yes, we want both liberty and safety, and we make efforts to achieve both at the same time, but if we can have only one of them, we'll choose liberty. -- Yoshie <http://montages.blogspot.com/> <http://mrzine.org> <http://monthlyreview.org/>