Is this a TAAT?
It doesn't have to be a race to the bottom, OP. I think it's good that current literature, whether online or printed media, is acknowledging the travails of 'the fourth trimester' and are offering suggestions for shaping this challenging time in a positive way to minimise exhaustion, support healing, establish breastfeeding and ensure sufficient time for bonding ‐lovely. For many women, even implementing one suggestion of the kind you referred to, could mean the difference between stress and relaxation, feeling overwhelmed and feeling cared for, exhaustion and recuperation.
There's an unfortunate and mean-spirited implication that new mothers who attempt to assert these kinds of boundaries in order to create the kind of early mothering experience they feel will support them as they find their feet, are somehow 'princesses' or some kind of bubblezillas. Just because many of us may have struggled with unsupportive or clueless partners and overbearing or intrusive relatives who did little to actually support or offer real help, it doesn't mean that a new mum shouldn't feel able to say how she'd like her first few weeks to unfold.
These books, blogs and other media help conjure possible ways of creating a supportive space for the people who really matter ‐the new family unit.
FWIW, I wouldn't for a minute think of visiting someone who'd just had a baby a) until I was invited, b) without bringing cake or snacks or lunch, c) without offering to get shopping in on the way, and d) without at the very least washing up afterwards or similar. I've delivered meals to the doorstep of friends with newborns, and left without even ringing the doorbell because it's not about me. Having a new baby is hard, without having to worry about also accommodating the needs and wishes of other people.