- "cycling is dangerous"

- "hiking is dangerous"

- "swimming is dangerous"

- "running is dangerous"

- "cycling complications"

- "running complications"

...all day long - just append certain keywords and you'll find many articles and studies to feed your subjective belief and win arguments.

I did and talked with a lot of people doing mindfulness meditation and none of them warned me against it. I don't doubt your claims but I think they are exceptions and just about any activity can be found to be dangerous when looking at the exceptions.