Except it doesn't. Vipassana courses are barely advertised, people come of their own volition, and participate for free. People are asked to try their method for ten days, not to change their lives without wanting to.

If they did advertise, they'd have scientific evidence that there are benefits from their methods. However, they don't use that, because meditation is not about proven benefits to them. It's about living a more compassionate and harmonious life.

Hardly a scam of any kind. I don't know why anyone would attempt to discredit it.