Because she's a girl, man. It's completely normal to see a older man/woman complaining when a young woman has to do something/suffer something hen the man does nothing. ''Why this young girl has to carry this groceries when those man are around doing nothing''?
Not only that but he sees her as a granddaughter. It's actually incredible hard to see a kid you saw using diapers as a adult. Specially when it's someone that you see as close to you. Fuck, I personally find it hard to believe that someone born in the 2000's can be considered a adult and have kids on their own.
The way you act is as if
when Vegeta says that Trunks is his ''baby boy'', trunks actually is a baby. To Vegapunk she is a kid. And no one helped her. Including the big robot. To Kizaru she's a girl younger than Sentoumaru. Of course, he will be surprised that she's actually a adult and comment on it. It never happened to you to see a friend of your mom commenting on how did you grow? It's the same thing.
If you see something problematic the issue is on you, to be honest. Not everything is made to fit your not so hidden fetish.
