He goes through at the end of each section and and lays out the elements of obstruction and lays out the facts that he feels pertain to each element.
Why does he then need to give his opinion if he’s given the reader the appropriate tools to form their own opinion? His conclusion would only have been used as political fodder to undermine his impartiality and undermine “the integrity of the criminal justice system,” that he says he’s trying to preserve? We already same democrats doing that before the report was released and saw republicans doing it while the investigation was ongoing.
He’d have to be blind not to see what’s going on and how people, including the president, refer to him. By not drawing a conclusion everybody should have had to read the report and decide for themselves but it can’t be said that his ultimate conclusion is evidence of his bias if there’s no ultimate conclusion.