I don't really go along with the distinction MsD draws either, to be honest.
For one thing, those who condemn sex and drugs and rock and roll very largely think their grounds for doing so are universal and objective, and that we who defend (or don't mind) those things are being blinkered and parochial in our embrace of a transient set of social norms instead of the great and eternal moral (or ethical) truths. Now, I don't agree with them, but if I say my position constitutes an ethic but theirs doesn't, I'm pretty much begging the question.
To but the boot on the other foot: you come close to saying, at one point, that the only ethic worthy of the name is a consequentialist one: one that focuses on weighing benefits and harms. Well, as someone who seems to be getting more and more Kantian all the time, I'd like to speak up for the idea that, for example, human autonomy is just as important as benefits vs harms.
For example, when I wish to do X (go about my business unmolested, perhaps) and you're pretty sure if I did Y (donate a kidney to a stranger, perhaps) I would increase the sum of human happiness, the right thing for you to do may nonetheless be to let me do X instead of Y. The argument being that even if the cost-benefit analysis favours grabbing a kidney off me whether I like it nor not, you simply may not use me as a means to an end like that.
Now, you may not agree with that (and you'd have some good, powerful arguments on your side), but I don't think you get to say that my position isn't even an ethic. The hell it ain't...