Do not find fault with others. If they behave wrongly there is no need to make yourself suffer. If you point out to them what is correct and they do not practice accordingly, leave it at that.
When the Buddha studied with various teachers, he realized that their ways were lacking, but he did not disparage them. Studying with humility and respect, he benefited from his relationship with them, yet he realized that their systems were not complete. Still, as he had not yet become enlightened, he did not criticize or attempt to teach them. After he found enlightenment, he respectfully remembered those n had studied with and wanted to share his newfound knowledge with them.