like patience, hope, courage/bravery.
Your straw-man example about marriage is easy to see, because it conflicts with a norm of our culture. What I wrote about is a more difficult view--that what culture norms asks of the ill may not be what the ill can give, may be questionably healthy, and may be shouldn't be a facile expectation of the ill, after all.
Culture defines how social roles play out in daily life. We learn these roles. We know what's expected and mostly we do it without question. Knowing these roles makes social life easier and less conflicted. Being ill comes not only with some pathological dysfunction but also with role definitions.
Cultural expectations for the role of mentally ill-person include 'sanctioned goodness' such as being patient, hopeful, and brave. But the socially sanctioned behaviors of the role aren't meant to only serve the ill person. They also serve all those who encounter the ill person. With respect to the ill person cultural role expectations may be situationally inappropriate and qualitatively the same as asking/expecting a depressed person to get up off the couch/bed and become cheerfully productive.
The goodness of normed expectations may be truly believed. Beliefs may be repeated with the best of intentions. I don't question that. On critical inspection, repetition of sanctioned role characteristics is inescapably, intentionally or not, a lot about the indoctrinating effect of reiteration of beliefs and expectations about how to play roles, even roles of mentally ill-persons.