It used to be completely normal that people who had political differences were friends - they viewed themselves as political opponents not enemies. Sad how that has changed.
I'm not surprized Dubya and the Obamas are friends. Dubya is not a racist. Apart from speaking Spanish fluently (and singing the anthem in Spanish) he was also the first to appoint African-Americans to high office - Colin Powell and Condoleeza Rice. Both paved the way for Obama.