Byrd actually gave an excellent floor speech explaining his reasons for supporting Judge Alito. After his tenure on the Klan, including some of the most odious statements ever made by any American in history, he will never have my respect, but I do have to give him props for that particular speech.
That's easy. Sheets simply believed his pals from the party that Alito is going to lynch blacks, brutalize women, and reinstate racial segregation. He simply couldn't vote no...