Keep in mind Luther didn’t set out to leave the Catholic Church. His original intent was to point out some mistakes so the church could fix them. It was only when the church leadership refused what Luther saw as a legitimate request that he broke with Rome and sought to save people by convincing them to leave the church as well. That’s when he began aiming his message at the masses. But back in 1517, Luther still saw the issue of indulgences as an internal church problem and had no reason to post his work for public attention.