My comment (before I even post this) I KNEW IT!
A study done in Germany has concluded that people who do yoga become more selfish, more arrogant, and develop bigger egos. The study concluded that this is happening because the courses are being delivered by people who are not qualified to do it, and the ideology is being delivered wrong. The study concluded that Meditation done by selfish people with big egos and selfish interests causes them to focus on their selfishness and ego, and causes their selfishness and ego to explode.
When course instructors overlook serious moral problems in the people they are teaching, and do not address those problems beforehand, the meditation works opposite to the way it should, and creates very bad people rather than helping anyone become a better person.
The report is very long and detailed so I summarized it above. The full report is here.