Whilst I do feel that this current trend is somewhat pretentious, I do think that it's up to the individual parents to do whatever they feel is right for them, particularly as far as not wanting visitors soon after the baby is born.
I'm sure many of us weren't looking, or feeling our best, in the days following childbirth, due to sheer exhaustion and pain (excruciating in my case!), and weren't feeling up to having visitors descend upon us. On the contrary, I was still excited and absolutely wanted to share the joy of our new babies with our close family and friends. Everyone is different.
As far as name sharing is concerned, it's not entirely unusual for parents to have not decided on a name, even though they've had 9 months to think about it, so I wouldn't worry about that. However, not sharing any other details about the baby, and not sharing a photograph with the grandparents, I think is rather extreme and hurtful. That has nothing whatsoever to do with the parents bonding with their baby. It's simply selfish and very hurtful.
As far as bonding with the baby is concerned, I've never known anyone in my wide circle of family or friends not to naturally bond with their baby, isn't it a natural instinct? I fail to see why so many new parents have the need to lock themselves away in order to bond with their babies. It all seems rather unnatural and unnecessary to me. But, of course, that's just my opinion, and I do appreciate that others feel differently.