Context: The joke is that early Roman emperors basically just needed the army’s backing. If you had a big enough force, the title was yours. The Byzantines turned it into a huge legal maze with all kinds of legitimacy rules, and eventually the Pope had to give his blessing too. The meme contrasts that with the old school ‘I have a big army, so yes’ approach. The Marcus Aurelius statue just nods along because he was one of the emperors who got there by being the best candidate, not by filling out paperwork.