What made Jonas realize that the community was never going to change?

In my opinion, Jonas finally came to the realization that no matter what he learned or experienced, no one else would never understand. Jonas could not live with what he learned, he could not live with the fact that his father killed the infant.... and that he lied. So Jonas decides he needs to go away.... to the place where he experienced the only love he'd ever know. The danger to Gabriel served to solidify any questions in his mind.