In Japan child nudity is not an uncommon sight in fiction, simply because it’s seen as a sign of innocence. It’s stopped being as much of a thing in newer works because Japanese Media is nowadays made with US localization in mind because if your shit becomes popular in America, it’s like getting a blank check.

It’s actually why in the Japanese Version of Earthbound Ness is naked in Magicant. (in the US Version he’s in his Pajamas)

Dragon Ball Z Kakarot actually has an explanation.

There used to be a fad where you took Furry Transformation drugs, it was all the rage when Goku was a kid

Somehow the Red Ribbon Army was behind the manufacturing of these drugs.

But the fad died down around Z, and most people went back to being human. Most people, you can still see animal people in the background shots of some of the Z Movies, I wanna say Android 13 and Lord Slug have them

I was telling my friend about the lore, and he thought I made up the name King Furry as a joke. Had to show him screenshots from DBZ:Kakarot to convince him otherwise