Why did martin luther post on a church door to publicly criticize the misuse of indulgences?

Martin Luther posted his 95 theses that criticized the conduct of the Catholic church at the church door because he believed this was the easiest place for people to view and decide to debate with him about these theses.

Explanation:

Martin Luther's 95 Theses are the initial milestone of the Protestant Reformation. Lutheran tradition celebrates Martin Luther and the "95 Theses" that were posted on the door of the Wittenberg Castle Church on October 31, 1517, beginning the movement for renewal of the Christian Church. Inviting people to discuss “theses” was the usual way of announcing “disputes” or “theological righteousness” among doctors in medieval Europe, involving teachers and students, even those who could not attend could respond to “disputes” (Theses). sending your opinions in writing to be read.

For this reason Luther posted his critiques on the church door, because it would be easier for his critiques to be visualized and for the intellectuals of the time to want to debate them.

what are the issues?