I don't know, even as a kid, I remember the allegories being pretty obvious in The Sneetches and Horton Hears a Who. The stories generally weren't that subtle in their morals, so this story doesn't seem atypical for Seuss.
And then there's the Seuss WWII political cartoons that I've seen recently due to their criticism of the America First movement of the time... which is interesting to juxtapose against the brazenly racist depictions of Japanese people that Seuss also did during that era.