It’s a political comics thing that has its roots in England around 250 300 years ago. The comic is meant simultaneously to be funny (and therefore disarming) and legitimate political propaganda. To ensure that the political propaganda message is not lost on the masses they label everything to make sure their message most clearly gets across.
For example, see this political cartoon from 1903. https://commons.m.wikimedia.org/wiki/File:Panama_canal_cartooon_1903.jpg