I would identify lack of respect and empathy as the primary source of the problem, rather than lack of education. The issue is less "some people under 30 do not know that treating others that way is not acceptable" and more "some people under 30 _do not care_ that treating others that way is not acceptable"

I mean, technically I suppose the empathy and respect may be something that you can teach, and if those are lacking then education aimed at raising empathy and respect needs improvement. However I think we are dealing with an issue that will be more difficult to resolve than just adding this material to high-school curriculum. Teaching empathy and respect is much trickier. (And with some people, it may be flat out biologically impossible (though google seems to be suggesting to me that researchers believe that psychopaths can choose whether or not they feel empathy, which is better than I suspected.))

I think we need cultural changes: teaching that is hard enough but almost impossible when some people provide an excuse shield anytime someone is called out on boorish behavior. This can't be an only in school kind of message - you have to see it actually practiced on a broad scale.