First, even if you define taking care of graduate students as part of their job and they fail to do so, it does not mean they are abusing their graduate students.
Second, the expectation of coddling is a very very recent phenomenon. Graduate students are usually expected to be functioning adults, not teenagers. Absorbing negativity and handling them by yourself is usually expected to functioning adults.
Third, academic supervisors are very likely to be people good at things, not good at handling people stuff. The major reason they are supervisors of their labs is they are good at things they do, not they are good at taking care of people.
> Second, the expectation of coddling is a very very recent phenomenon
I think the expectation of (and complaints about!) coddling are actually historically very well trodden. There's a great reddit thread about this [1] which details historic complaints from the Greco-Roman era all the way to the present.
