No one really cares about them? You can certainly give them away before they're finished weaning. Presumably the legal assumption, particularly with financial transactions, is that the person making the purchase/obtaining the animal is aware of how to care for young animals. It's not like it's particularly impossible... usually not even that difficult, just tedious. Family's raised up a few cats from similar conditions, so there's some exposure to it, f'me. Probably should be some kind of waiver to sign or summat like that, but... well, it's paperwork for a small subset of animals. Not much incentive to actually have laws for it. Egregious stuff gets bundled under animal cruelty. The occasional neglect death or whathaveyou is generally just kinda' shrugged off.
In any case, animal cruelty requires someone pressing the charges, and sometimes wouldn't stick even if the person shot the heads off kittens or something of similar nature (this has happened more than once in my area, for what it's worth.). Most areas and most people don't really care or have enough awareness to do much on that front, and in most places I'm aware of in the US, in any case, there's not really that much in the way of legal protections for animals, as animals *shrugs* As people's property is a different story, but...