Hi azzu02,
I don't understand either about the kittens, is it really physically dead or just literally dead?
Nevertheless, I agree with you & Kuntum, that if people are interested to keep the stray kittens, they should keep the mother as well, as a whole to help, just keeping the kittens won't be much help rather than making the mother cat grieving for loss. The nature of mum & babies' bond is broken.
This may sound more to emotion, but after all, we don't want this to happen.
Kuntum said is best, these people are somehow lack of knowledge. I see it this way, if this is a doing of a kid / teen, their parents are to be blamed for not giving full attention to what their kids are doing, simply carefree.