there are reasons beyond puritanism to regulate illegal drugs and prostitution, mainly having to do with the public health issues behind them. I know that the concept of 'public health' is not part of the libertarian mantra; it is, however, a real-world situation where individuals don't live in vacuums. Particularly when it comes to what used to be called 'social diseases,' which are, inevitably, transmitted via prostitution and drug use, which in and of themselves are irrevocably linked.

That whole argument just gets to the heart of the matter: the human condition is an ongoing tension between the desires of the individual against the needs of society. And libertarianism in its purest form is so biased toward one side of this as to be igorant (yes, that's the word I used) of the needs of society. That is why it is appealing intellectually but is ineffectual in practice, IMO.

As for public schools, by that very designation I think you are pointing out the necessity of them: society needs well educated people (for any of a number of reasons) and therefore has designated that education shall be provided as a public good. It's beyond an individual decision.