Yeah, I know that much, but I'm talking specifically about the low effort ones.
I have seen some guys selling AMAZING characters designs, and for these I get the price and the whole "adopt this character" thing, but for each one of them, there are 3 artists that are only trying to get some easy money with lazy stuff.

From the two I remember the most, one was this guy selling 8 recolors of Cinderace (that football bunny pokemon). It wasnt even an unique take on it, it was just the same drawing of that pokemon, but with different colors.
He doesnt owns the rights for the pokemon, so selling adoptables of it is rather pointless? You cant say you "own" it, GameFreak/Nintendo does.

The other one was this guy who was selling 10 variations of the same shark girl thing. Same face, same body, same hair, same drawing, but different color. Not even different traits or anything, just the body color and some stripes.
Who owns the character here if they are all the same with almost no variation? If someone buys one, then decides to change the colors, is he in the wrong? It is his character now.
He sold them for a certain price, but if you wanted to ref sheet for the BACK of the character, it was almost twice the price.