He thought he had Gods word behind Him.
Nehemiah 8:1 And all the people gathered themselves together as one man into the street that was before the water gate. . .. And he read therein before the street that was before the water gate from the morning until midday, before the men and the women, and those that could understand; and the ears of all the people were attentive unto the book of the law. 4 ..... 5 And Ezra opened the book in the sight of all the people; (for he was above all the people)
No doubt his thought was if the scripture is for me, who cares if the press is against me.
Claiming an imagined mandate is indeed a dangerous thing! Lol!