He's a revolutionary. As General he attempted a coup in 1992. It was unsuccesful, or so they say, because in 1998 there was nothing unsuccessful about his election to President.
He is popular because he is sincerely a man that wants to elevate people to a standard of living they have never been afforded. His 'fall from grace' during the Bush Years is due to the fact he is concerned for the national defense of Venezuela and it's sovereignty.
His concern comes from the same source as any other small country viewed as being in disfavor of the USA, it stems from the aggressive nature of the USA as well as the unpredictable us of it's military.