Those links are a fair reflection of my personal views. As a teenager, I was a rabid prescriptivist. I was partly raised by my grandmother whose response to the question "can I have some chocolate" would be "you can, but you may not." Although I finished formal education after high school, I have continued my love affair with language as a hobby throughout my adult life, and through the experience of attempting to learn several different languages, and learning more about the wondrous history and diversity of my own, my views have shifted. I went to the extreme described in the first link, the "anything goes" sort of descriptivist, before swinging back to where I am now. As Humpty Dumpty said, "When _I_ use a word, it means just what I choose it to mean -- neither more nor less.' My view is that the principle he expressed holds true of a language community as whole. That illustrates the balance between prescriptive and descriptive. If EVERYBODY used words to mean whatever they chose, communication would be impossible. However, when ENOUGH people start using a word in a particular way, then it is fair to say "that is what that word means." "Nice" and "decimate" are examples of this sort of usage-based shift in meaning.
It's worth remembering, too that many of the prescriptivist "thou shalt not"s have absolutely no basis whatsoever in real English grammar. The rule against splitting infinitives, for example, is inspired by Latin, a language in which it is physically impossible to split an infinitive. The prohibition on ending a sentence with a preposition and the fierce contempt for the singular "they" are further examples of prescriptivists simply making the rules up as they go along, and then trying to insist that everybody follow them.
That said, it is obvious that when learning or teaching a second language, a healthy measure of prescriptivism seems inevitable. Coming at a language for the first time, students are going to need a framework of rules to give them some sense of direction, and a yardstick against which they can measure progress. Although this is necessary, it's more important still, in my opinion, to remind them that, as Humpty further said "The question is,' `which is to be master - - that's all.'" It is my view that devout prescriptivists have set up a corpus of rules to be their master, whereas language should always be servant of its speakers. We are the masters of our languages, not t'other way round.