Are we not allowed to criticise writers anymore then?
Criticising a writer would be saying that you though the middle sagged a bit, or that there were a few too many descriptions of sunsets or blisters. (Or that the Simon Armitage mystery went on a bit longer than was amusing, which I thought.) This is picking apart someone's personality under stress.
It’s the pure contempt she seems to have for the massive majority of people.
Look at an average day of Mn AIBU threads about dismissive/unpleasant behaviour among the Great British Public -- someone hitting a child, not controlling their dog, being verbally aggressive in a café, jumping a queue, failing to offer help when it was needed, failing to respect personal space, being insulting etc etc etc.
Now imagine dealing with that when you're already vulnerable, reeling from the shock of a terminal diagnosis for your husband, suddenly going from being a farmer with land and animals and a business and a house you've rebuilt from scratch over decades to being suddenly virtually penniless and homeless, in pain from lugging a rucksack along a steep path every day -- and you don't have anywhere safe that's yours to retreat to from other people's behaviour, apart from a tent that a man and his dog deliberately urinate on, knowing there are people asleep inside, on one occasion.
I think you'd feel as if you'd had all your skin stripped off, and at the mercy of other people's behaviour, good and bad.
And there are some accounts of very generous behaviour from people, and people who are just nice, as well as the awful ones. There's the pink-haired girl who gives them free pasties, and the nice young backpacker guys they meet near the beginning, and the soldiers on manoeuvres, and the wine millionaire who invites them in for dinner and lets them sleep in his garden, and the group of surfers on the hippie campsite who give them beer.
And they are both kind to people, too -- Moth shakes hands with the barrister who has just won the case against them in which they lose their home, and, despite living hand to mouth themselves, they give half their rations to a homeless man in need (who tells them to fuck off). 