I wouldn't exactly have said this was an example of 'racism is good' - it's more of an example of 'know who your enemies are, and how to face them'. After all, as Mighty Mouse puts it, 'Don't you know what cats DO to mice?' From a mouse point of view, it is perfectly reasonable to hate and fear cats - cats are the ones that eat you! And even considering that, I think the message here is actually quite a peaceable one. After all, in many respects Lumphead is actually right - he's just overenthusiastic. He loves everybody and doesn't want to hurt anyone, which is a noble creed, but which Mighty Mouse finds exasperating, because cats are the natural enemy of mousekind, and so he therefore sees it as natural for a mouse to hate cats, not love them. But Lumphead doesn't love cats BECAUSE they are mousekind's natural enemy - he's simply misinformed; nobody has ever bothered to tell him WHY mice hate cats. And even once he realizes this, he doesn't change his position - he goes 'well, mice hate cats because cats eat mice - so I'll just teach cats to love mice instead, and eat other things!' This doesn't work, of course, but it does cause the cats to run away, and, as Mitzi puts it, he 'has the right idea', and shouldn't stop trying. It's basically an argument between hard-headed realism (Mighty Mouse) and idealism (Lumphead) - and idealism wins! So in the end, it's the hero who learns a lesson. I wouldn't say the message is one of intolerance at all.