I mean it's both, Oda took advantage of the joke to insert Kaido as it was his saga
No, the mistake in that argument is completely ignoring
why Oda used Kaido specifically in the comparison. Oda’s joke is not simply “mom > Kaido” as if it were just some random gag. The point of the joke is to
praise mothers as the strongest beings, and to do that he needed the
absolute maximum strength reference within the narrative. If he said “mothers are stronger than Usopp” or “stronger than Jinbe,” the joke would lose all impact. It doesn’t make sense to use a mid-tier example when the intention is to emphasize grandeur.
Oda needed the
strongest strength benchmark in the verse at that moment, and that reference was
Kaido, the “Strongest Creature Alive.” That’s why he says “even stronger than Kaido.”
In other words, to elevate mothers, he intentionally uses Kaido as the
top absolute reference. The joke works
precisely because Kaido is recognized as the pinnacle of strength. If Kaido weren’t the strongest, the joke would carry no weight.