... Is that it (sometimes) throws out the baby with the bath water. So to speak. Like if someone claims that xyz practice is really great, because it helps clear your mind, teaches you to focus, and at advanced stages, you can fly... Well, sure, science is probably going to be able to fairly readily toss out the whole flying bit.
It might even be able to show that the practice is no better at clearing someone's mind or teaching focus than some other generic goofy practice. And maybe it's not. But that's maybe because the other goofy practice and the one being investigated both have some real effect at play. And even if that effect is a placebo effect, well... Science shows that the placebo effect is real, right? So... What do these practices have in common, really? If we study it in detail, and find the common link, can someone who knows what the science says still get the benefit? Can one get benefit from placebo that one knows is placebo? If not, but not knowing allows real benefit, then it seems to me that someone somewhere in science needs to make some sort of allowance for some of this stuff. Somehow. Carefully. But how? And is this done today?
Or, if we can benefit from known-placebos, then start handing them out.