In defense of yoga, the consensus among professional (credentialed, full time...) instructors is that crappy teachers are dangerous.
It's amazing how many serious mistakes you see in mainstream venues. People doing tree (standing on one leg, with their hands above their head) with their foot flat against the side of their knee. You only see this is bad if someone points it out, but you will eventually get an injury if you do that long enough. Just an instance that everyone has probably seen.
This is unfortunately yet another case of Sturgeon's Law
("90% of everything is crap").
Exactly the same holds in aikido. I can't say for sure that my own classes aren't part of the 90%, but there is certainly a lot of aikido out there that is dangerous in any of several ways. Either you are going to hurt yourself in the long run, or your practice is giving you bad habits that will let someone else hurt you at some point. Not to mention the chance of you damaging your practice partner.
My approach to yoga these days might be described as having a dialogue with myself, where sometimes I manage to sort out some issues. A lot of the time it turns out that I feel good afterwards too.