I understood his point as "it isn't scientific, therefore we can't be sure it's helpful, therefore it shouldn't be the go-to advice for anyone suffering from me

I understood his point as "it isn't scientific, therefore we can't be sure it's helpful, therefore it shouldn't be the go-to advice for anyone suffering from mental issues". His phrasing is aggressive and generalizing, and he should've probably used a better choice of words. But it's a point I somewhat agree with. I've personally tried different kinds of therapy for my issues, years at a time, and I can say with certainty that my time was wasted. I also personally know multiple people who've had similar experience. One reply I can imagine is "but maybe you didn't put enough effort/spend enough time" - in which case I'd like to ask, in what way does that argument differ from the religious argument of "if God doesn't help you, you didn't pray enough"? Another reply I can imagine is "it doesn't work deterministically, psychology/psychiatry is not an exact science" - in which case it would prove the original comment's point. It might as well all be bloody hogwash, and yet people recommend it all the time because it's "science".