The only point I want to make now is this: prior to the modernist vipassana revolution, much of what we take to be orthodox now would have been anything but. I don't think there is any evil in folks choosing what paths they want to take, and I for one am not going to try a propose a homogeneous Theravada magga. There is no shame in the fact that these movements are modern and recent and at their most legendary a "rediscovery" of a special technique passed through the Burmese masters originally from the Buddha. But if we imbue the orthodox with a particular value and then project that orthodoxy back through time, then we devalue 2 millenia of a diversity of magga and praxis philosophy.
Having experience with Mahasi style meditations, I don't find them to be evil or necessarily destructive. And at their best I found them revealing and beneficial. I moved away from them because I believed that for me they only reified my own sense of egoism and amounted to a sort of self-hypnosis. However, I believe these outcomes were relevant to my background, psychological, and mental effluent, and I certainly do not project that view with certainity on to any other practitioners of modern vipassana practices, many of whom have found the practices to be profoundly illuminating. I say this as a disclaimer, because I don't have an antagonistic view to these practices and I'm wary that some folks feel like they're under attack. You're not.
But to the simple question: did the buddha teach vipassana meditation? The short answer is no, as far as vipassana meditation refers to the modernist vipassana practices. But this leads to other questions,
Does vipassana meditation cultivate the Buddha's teaching?
Clearly the answer to this question is yes as far as the practitioners are concerned. And clearly this is not just an optimistic answer, but is an answer that pays serious attention to the Pali Canon and varieties of Pali exegesis.
Is vipassana meditation a serious and committed application of the noble eightfold path?
Clearly the answer to this questions is yes as far as the practitioners are concerned. And here's the rub: there's no shame in fresh interpretations of Buddhist praxis. The Buddha did not teach Buddhism, or probably a lot of what for 2 millenia has passed as Buddhism. "Buddhism" is the living tradition of trying to heed the dhamma of the Buddha. As Theravada Buddhists, we are committed to realising the lessons of the Buddhadhamma in the Pali Canon, those scriptures we hold to be the closest to the words from the Noble One's mouth. All Buddhisms, ever, are a serious and committed attempt to understand and realise the Buddhadhamma. This is why there is no shame in the reality that modernist meditative movements have no analogues for probably the best part of 2 millenia. What these practices are, are serious, committed, faithful, loving attempts to understand and realise the Buddhadhamma. And so in that sense they are exactly what the Buddha taught.