The odd part is that in the wild, the kitten doesn’t stay with the mother all that long.
That reminds me Cruela.
My cat Kika once got pregnant. We were able to give all kittens new homes, except one - that stayed with us. She grew into adulthood, not only pampered by the humans but also by her mum Kika.
Cruela would find an open window, take a walk, then come back after a few hours. And then when she was back, she’d ask Kika to be licked. And every single time Kika would lick her manchild womanchild catkitten daughter for a few minutes, then meow angrily and paw her once or twice, as if saying “you’re clean now you adult baby, now sod off!”. Every single time.
It is the result of Japanese law. Further info here (in English) and here (in Japanese).
As such, yes, the Japanese government is also to blame. Plus any other government playing along with this crap, be it from USA or Brazil or whatever.