People are People
A great Cold War breaks out between the Zooks and the Yooks over the issue of which side of the bread should be buttered. This is the only really substantive issue dividing these tribal groupings and their only other apparent difference is a preference in the color of their clothing. Aside from that, these two societies that wage war with each other unto the brink of mutual destruction are—based on the evidence available—utterly identical. The underlying theme here is that people are people and most of the differences which have brought them to war throughout history have tuned out to be based on the slimmest and most inconsequential of differences. Not all issues have been inconsequential, of course, but certainly a robust majority.
Nuclear Proliferation
Quite notably, the Zooks and Yooks never heat up their war over butter culture past the simmering point. There is never any boiling over into outright hot war between the two sides; it is a Cold War in which energy put into arms goes toward producing increasingly sophisticated weapons of “deterrence.” This reflects the lack of a hot war erupting between the militaries of the U.S. and the Soviet Union and the rise of a Cold War which instead saw billions of dollars wasted on weaponry neither side either wanted or ever intended to actually use. The result being, of course, that while war was avoided, the cost of war on society and progress was not.
Territorial Butterings
The driving theme of the entire story is the conceptualization of the absolute lack of military intelligence when it comes to issues which can only seem to be resolved—temporarily, in most cases—through genocide. For those who think that Seuss invented the ultimate ridiculous reason for going to war with his disagreement between the Zooks and Yooks over which side of bread is best buttered, one should take a moment to become more familiar with an actual historical engagement known as the War of the Oaken Bucket.