"But they're practicing wrong! They're actively wasting their time!" the man told me. We were talking training methods in martial arts.
He argued with the people in his local community, but to no progress. After being outspoken for a few years, they seemed to avoid him.
People aren't persuaded by facts. They're moved by emotions, the stories that they tell themselves.
They'll believe people that they like, and avoid ideas shared by abrasive people. Regardless of the facts.
When you're told that everything you're doing is wrong, it makes you defensive. You search for weakness in the attack, find an excuse to avoid it.
If you want to change others, perception and stories matter more than facts and logic.