1. While Hoover was maybe rather unpleasant, Himmler played in a different league, so to speak.
2. Technically, whilst Himmler was in charge of the SS, and therefore of the SD, the SD was run by Reinhard Heydrich.
3. Generally speaking, the leaders/commanders of secret services or police forces tend to have a rather bad reputation (although, as suggested in 1., "bad reputation" can mean a wide array of things). This is, as far as it can be determined, due to several circumstances, all based on the personality and morals.

A) Ascending to the leadership position, especially in competitive environments, such as secret services, tends to favour personnel with competitive, aggressive leadership.

B) Also, secret services often handle tasks and conduct operations that are, at best, morally dubious or need a certain justificational logic. Therefore, the personnel tends to be consisting of realists that focus on personal principles, not morals.

C) The measures taken that receive a wider public attention are likely to attract opposition, who characterize the personnel as "bad".

Therefore, the leadership personnel of secret services is likely to show traits that are usually looked down upon. Also, they are portrayed negatively by their opponents.