They have a history of supporting animal abusers, one example of which is when Michigan was considering creating a registry of animal abusers to prevent them from being able to again adopt or purchase animals… Wayne Pacelle of the HSUS was opposed to this idea. Nathan J. Winograd wrote a more in-depth article on this particular issue which you can read here, on the Huffington Post.
The HSUS also groups popular pets such as snakes in with “dangerous exotic pets" such as bears, big cats, and primates. They’ve also earned a D from CharityWatch and are listed as Donor Advisory by Charity Navigator, largely because of their poor use of their funds.
Approximately 20% of their funds goes to paying salaries, Pacelle’s salary being more than $270,000 a year. After Hurricane Katrina the HSUS raised $34 million for New Orleans, and spent only about 20.6% of relief efforts for pets and residents.