I think it says a great deal that for most of us as children, including myself, we never thought a single negative thing about the various racial stereotype jokes back in these shows. Or even the ones about smoking and things like that. We accepted it just as silly 'toons, nothing racial, nothing negative at all. It didn't bother most of us, it didn't bother me, because we didn't have a single racist bone in our childhood minds, never really knew anything about racism in general.
I don't have a problem with the warnings since a lot of the people that are going to watch these old cartoons will be adults revisiting their childhoods. The only aspect of it that I don't like is that it strips away the chance that children of today, watching these things for the first time just as we did years ago, will be able to also view the toons without any hint of anything racist. If they can read they'll see the warning, and make connections that they may never have made in the first place had there not been any warning. It rips the innocence from it that we had when we originally watched them.
I'm not sure if this makes sense to you guys, or if I'm explaining myself the way I intend, but there ya go.