I am happy to clarify, though I believe I did when I specified that the word meditation is associated with the observance of suffering, its origin, its extinction and the path leading to its extinction. There were teachers who taught meditation before the Buddha but one also needs to understand that they were incomplete forms of mind-training which did not lead to the realization of the conditioned nature of reality. [1] The Buddha trained under the best teachers at the time and synthesized them into a whole practice, which when followed to their end led to total liberation, or nirvana/nibbana.
Many of the techniques you highlight descend from the same lineage: mindfulness (vipassana), lovingkindness (metta), and nondirective (of which transcendental owes itself to, Zen was its predecessor). It should be no surprise that the scientific evidence we have available to us has verified the efficacy of mindfulness, has verified the efficacy of lovingkindness. [2]
A meditator's journey may take them through a host of techniques. What's important is they are backed by ethics and deep understanding of what practitioners thousands of years before us were writing. That is a foundation to build on. The Buddha and the teachers who followed built on this foundation. The Chinese synthesists, Mahayana, Vajrayana, all of them established themselves in the foundation of what came before.
The foundation is a tripod. It is not "just" concentration or "just" ethics or "just" awareness, it is these three working together. [3] If you kick one leg out, the whole thing comes crashing down.
Let me also clarify what I mean by dangerous: meditation must be grounded in ethical action, in right understanding of the techniques because one can very easily come to assume a new set of delusions to replace their old, which leads to poor outcomes for themselves and others. People have been dragged from retreats screaming because of latent mental illness or they perceived something they were unprepared for. I myself have observed the total dissolution of self right before my eyes. I was not afraid, I was ready. I owe that fearlessness and confidence to my teachers who selflessly taught with no expectation of monetary gain.
Money itself corrupts the relationship between teacher and student. And we have decades of abuses from self-proclaimed gurus to back this.
Those who declare themselves authorities to remove ethics or wisdom from a system of mind-training because it smacks of religious devotion need to seriously examine their motivations for doing so.
The dhamma is free for anyone to pick up. I could recommend a host of teachers who will give days and years of their life to any prospective students who wish to take up the path, completely for free. And then when you turn your mind to gratitude, to lovingkindness, it will be easy to find a person for which to be gracious to. I owe my life to these people.
I'd like to conclude by really pushing the creators of this project to reconsider associating Chorus with meditation. Even the Wim Hof Method is just the Wim Hof Method.
Chorus on its own is a great name.
[1]
https://en.wikipedia.org/wiki/Prat%C4%ABtyasamutp%C4%81da
[2] https://docs.google.com/spreadsheets/d/1m_tiYlDIyNpp6WGUgKd5...
[3] https://en.wikipedia.org/wiki/Threefold_Training