The assumption driving such worries is that individuals are inherently hedonistic and, absent the threat of punishment in this world and damnation in the next, they'll seek only their own pleasure and ignore family and community, ripping the social fabric.
But life doesn't work that way. Individuals don't simply discard an old order in favor of no order. They look for a new order that better accommodates their personal goals and social needs.
Citing the holy writ of F. A. Hayek, Dalmia refutes the slippery-slope assumption of declining sexual morality. Hayek wrote: "Flexibility of moral rules ... makes gradual evolution and social growth possible, [allowing] experience to lead to modifications and improvements." Dalmia herself contends that the diminished radicalism of 21st century feminists, compared to the extreme demands of their mothers or grandmothers, results not from religious exhortation but from practical experience. Women supposedly have learned what works and what doesn't, what demands are reasonable and which are impracticable or simply undesirable. Examples like these prove that "removing government from the business of enforcing morality doesn't mean that individuals will celebrate their liberation by smoking crack and throwing orgies. It means that they'll become active agents in choosing their own morality," -- without assuming a right to steal or kill, either.
The weak point of any slippery-slope argument is its assumption that people can't reason themselves off the slope, that a downward spiral of rationalizations is inevitable. Dalmia deserves credit for hitting one such argument at the weak point. I only wonder whether she recognizes the similar weakness of slippery-slope assumptions closer to the libertarian heart.
Libertarians share with most American conservatives an assumption that "dependency" upon government saps our vitality as our people, that our economy will inevitably stagnate if not collapse if millions of people keep on the government tit. The slippery-slope assumption here is that people who receive long-term government assistance in the absence of jobs will lose the desire (or "incentive") to improve their lot by working. If the cultural conservatives worry that "individuals are inherently hedonistic," libertarians worry that many are inherently lazy. If cultural conservatives believe that the social fabric depends on "the threat of punishment in this world and damnation in the next," libertarians believe it depends on the threat of starvation or some kind of deprivation in this life. Only that, it seems, will drive some people to make themselves useful to society. But by analogy with Dalmia's argument against the slippery slope, shouldn't we expect an effective welfare state to evolve in the same way as the new sexual order, with people defining a new order based on practical choices instead of succumbing to self-indulgence? As a group, libertarians appear to reject the old assumption of human depravity that justified the recourse by moral (or "cultural") conservatives to punitive state power. Dalmia, at least, explicitly rejects the assumption of depravity in the realm of sexual morality? Does she also reject the assumption of depravity in the realm of social welfare? She could still argue the unfairness of "robbing Peter to pay Paul," but to be consistent about human nature, she should not assume that Paul will be nothing but an indolent parasite all his life, or that his example will encourage Peter to become one as well. It's more likely that Dalmia or like-minded libertarians would attempt to explain why the sexual-morality and social-welfare scenarios are fundamentally different. It'd be an interesting argument to read, but I'm not sure how convincing it would be.