What I agree with...is from the perspective of dealing with anxiety about being discriminated against that is something we who are, or who are intimate with the mentally ill must cope. The anxiety, anger, despair, and frustration over stigma and discrimination have to be managed at a level that doesn't add another layer of dysfunction to you, me, other mentally ill folk, and the persons in our lives.
That's very very true. Anyone who has been around the Mental Health Support group for several years has seen anxiety and fear about stigma be a burden and it's obvious that it can be a font of dysfunction.
But, I must disagree with the second part of your post, the concept that we have something wrong with us and thereby can't seek freedom from discrimination in a way similar to blacks or the LGBT.
One of the ways you can test the ethics of a particular idea is to move it to other similar circumstance to see if it remains true. When I do that with your argument and apply it to persons with physical disabilities rather then mental illness, it looks just like a rather hollow argument against the Americans with Disabilities Act. The physically disabled have things "wrong" with them, and yet American society generally sees that discrimination against them is harmful...and a majority of Americans agree that reasonably assisting them to their highest level of function is desirable for the disabled and for society.
The argument "we are flawed and don't want to be what we are anyway, so don't have similar need to be free of unfair discrimination as other minorities" is imo flawed, and is also too narrow in consideration.
The movement to end discrimination against the mentally ill isn't, and never has been, pushed by only the mentally ill.