Not literally zero effect. But I wouldn't be surprised if the majority of the effect is the same as how propaganda works.
I take it as similar to inversion tables. Could it help some folks with their back pain? Absolutely. Does it do so for the reasons they put forward? Highly unlikely. (Acupuncture is similar. Homeopathy? Maybe...)
So you're claiming that it's mostly placebo? That is absurd to me. Why wouldn't sitting down and doing a specific mental activity for 30 minutes a day (e.g. paying attention to breath) change something? It seems very obvious to me that it would train the mind in some way. This is a genuinely bizarre take
Meditation isn't really a spiritual act though, it's simply a form of mental training. It is like learning, or doing puzzles, etc. Do you doubt those things?
The spiritual part is how to frame the results and shifts that come from long-term meditation in a helpful worldview.
Have you tried it by the way? It sounds like you aren't quite aware what it even is
