some of these nikkas don't think on a level that deep or understand the idea the of the story branching off into different stories on a deeper level if it's not "main character fights and beats the new strong 1
villain"
It wasn't even that deep, it was just well constructed. You see the the evolution of ants as creatures only concerned with base desires like eating and reproducing to wanting to create societies or wanting to please. Feeling things like love, respect, anger, jealousy, etc.
And as the ants became more human and relatable, the humans started looking more racist and evil. Its not an accident that the most human looking of the Royal Guard was the most manipulative, cunning, and emotional of all the ants (Pouf).
You see Mereum, a being who had every right to feel he was superior to humanity, try to have a conversation with Netero so they could reach a compromise despite the fact that he was clearly able to kill him any second that he wanted.
Mereum, who had every reason to hate humanity and could have spent his last minutes trying to enact revenge, chose to free humans believing that their individuality had as much right to exist as they did.
He chose to die doing what he loved and with who be loved, playing a game, rather than throwing a "tantrum" like Gon and Netero did when facing their own reality.
Mereum is literally a GOAT-tier antagonist. Perfect representation and foil to the savagery/racism of humans. Look at how monstrous and demonic Netero looks at the end of his fight when compared to how human the King looks.