Ugh, I can't stand it when people scold (or at least chide) someone for their coping methods. I totally agree with you (and so does science): learning to accept (stop struggling against) unpleasant but probably permanent situations as being (again probably) permanent (or at least not something that we have the ability to change) is often necessary for finding peace and even for being able to pull out of a related (secondary) depression.

For example, being legally blind isn't something that's a source of angst and misery for me. I grew up knowing I'd never see any better (nor that it would get any worse), and there probably wasn't anything they could do to fix it someday, so I just got used to it. And that's okay; that isn't “negative” in an unhealthy way.

It's like the serenity prayer says: we might as well accept that there are some things we can't do anything about and that aren't necessarily likely to get better on their own, but instead we can just focus on what you can do to make other things better. I don't know why this prayer isn't more popular outside of the AA community: for anyone of a religious inclination, it has great wisdom for people in all sorts of situations.