To portray his positive side, the practices he introduced seem to have helped crime detection/prevention world over. Especially his agenda to use finger prints as criminal evidence, begin a practice of collecting them and building a central data base for finger prints. He is portrayed to have made the Buerau of Intelligence from an agency of no power to the very powerful FBI that it i today. Yes, you need to be a unpopular and a prick to build that kind of beast. And he happened to be the one. And I didn't think he was any more or less biased than an average human being.
There is a unnamable magic about watching DeCapiro play this role. I guess it has to do with the accent and the way he enunciates words. The force of Hoover's personality has been brought out well. Agenda-driven. focused and ruthless men impress me. Even if they are bad men. And in showing all that very well this movie thoroughly entertained me.