James Bradley is a graduate of the University of Wisconsin at Madison and is not atypical of U-Mad graduates with his pessimistic views of US history.
Bradley’s book claims to be a ‘secret history’ but everything he sources in the book comes from the public domain. Even your NYT review says as much. The only not-so-secret here is Bradley’s revisionism.
TR was not without his faults, I agree. His views on taxation were not so much meant to foster leftism as they were intended to undo the power of the trusts and the men behind them. In that respect I can appreciate his tax policies as they were intended to level the political power of certain people. In retrospect it was wise for him to do as he did given that his policies blunted the communists 20 years later.