Hoover's political career was generally quite horrific - he embraced the first sort of "southern strategy" which actively courted racist whites and purged blacks from leadership roles in the Southern GOP.
Not to mention blaming the Great Depression of Mexican Americans to justify a mass deportation program. As admirable as his humanitarian work may have been, his actions as President and his conduct during the campaign make it impossible for me to consider him a good person.
He still wins in this poll though.