That’s one of the big reasons. Hoover was deeply misguided in what he did and how he did it. But at the same time, he was definitely more mission-driven - in the sense that a large part of his motivation was to establish the FBI as an investigative agency beholden to the country, not any politician in particular. It’s just that his interpretation of “what’s good for the country” unfortunately included a lot of somewhat paranoid and violently reactionary motivations, because he perceived a lot of relatively benign political disagreements as personal attacks on him and/or the agency.