You've defined family, not family life, which is different.
LeQ, people do feel that bond with their kids, but it may also be that for whatever reason, boarding school works for that family at that time. A colleague of dh's had to put his kids into boarding school after the death of their mum whilst he was at sea. Their gp's couldn't cope with them, and it was better for them to board until he decided whether to leave the Services or not.
Kids at uni may be legally adults, but they're not quite there mentally, ergo boarding school for older children.
People don't have to defend their right to send their child to board; it is their right to do so, and also their choice. It is not your choice, but it is theirs. What is to to you that they do so? It's not illegal or immoral. I feel for the poor kids who have a high flying mum, and who are constantly left with the Nanny whilst Mum runs her company.
Your ideal of how to mother may not be everyone's; I was quite happy to leave ds in the care of his grandmothers from an early age for a fortnight at a time from when he was about 2, and they lived 3.5 hours away from us.
Swallowed, I consider my Mum part of my family, but we don't live together, neither do I live with my db who is also part of my family.
Having seen the descent into hellish behaviour by some students who were fostered because the foster cares couldn't deal with the experiences of the child, the behaviour of the child, or abide by the rules that had been laid down when they fostered the child, I thought at times that a residential school that dealt specifically with abused children might not be a bad idea. I have a friend who works in a special school for lads with EBD, for whom there is no other place in the system and it is full boarding. It works.