I'm sure it must be blasphemous to not capitalize that "dude." And that's all I have to offer.
But... but... but, that kind of thinking is antiquated and alienating. Not capitalizing the word shows how hip and happenin’ and modern we are. After all, capitalizing it would mean that we be talkin’ to someone we think is higher than us and that’s just... just... so... antiquated, dooood.
#;^)