I'm one of those "DUDE!" kinda gals. I find myself saying it to my friends all the time. I never thought of it as disrespectful as well. But if caught said enough times, it could be annoying. lol...

Its just one of those words that is used for everything.
("dude, I'm so sorry,) was one of them. ("Dude, that was deep") and at times it is used for comedy. ("Dude, wheres my car?") lol! One of the famouse ones. lol.