I really think its a generational thing - and its going to take another one to completely wipe it out. I've had to break myself of the habit of saying something was "gay" when I was growing up - you're right that its often used as a casual goofing around insult with no malice behind it, but once you're past a certain age (or actually get to know someone from the GLBT community) you should really know better than to just sling it around. Hell, my best friend is gay and even when he says "boy that's gay" I still can't bring myself to use it casually.