Well, the self-answered Q&A you link to has a good number of upvotes on both the question and the answer, so obviously people (myself included) think that it's worth reading.
I strongly agree with posting self-answers if you find the answer to your question. In fact, I've answered my own questions too. For example, I recently asked several questions about 1984 (one about why O'Brien wasn't a thought criminal for admitting to the Party's malice and another question about why O'Brien claimed that the party didn't believe in solipsism. I thought about the questions more after I posted them and finally realized what the answer was, so I posted them as self-answers. They're not perfect answers by any stretch of the imagination, but both of them got upvotes and have positive scores, which seems to imply that someone found them useful, so obviously they were worth posting.
Some of this is also a cultural thing that's unique to each site. For example, for whatever reason on Stack Overflow self-answers tend to be judged more harshly than other questions, which I strongly disagree with because if someone's supplying useful information then we shouldn't discourage that. Self-answers and their accompanying questions should be assessed exactly how you judge other questions and answers - is the question clear, useful, and reflecting research effort? Is the answer useful, clearly written, and presenting valid information and justification? (I'm being careful about how I phrase the last one - "correct" can be a little more ambiguous in controversial cases, but an answer that I disagree with but still presents correct information and valid reasons to agree with their views can still deserve upvotes).
Point being that I think we should encourage people to share information here, especially information that's difficult or impossible to find elsewhere. The main point of Stack Exchange is to serve as a repository of knowledge and to enable people to share information with each other, so if you have useful information to share with the community, by all means please share it so that it can be documented here for the benefit of current and future readers. So, if anything, I think that Q&A about obscure works could be very useful to someone who was looking for more information on those works.
With regards to the user who quit over your other self-answer, I wouldn't worry about that. I agree with @Hamlet here - it seems like a really petty reason for the user in question to quit to me. Obviously, the fact that other people upvoted the Q&A you link to indicates that other members of the community disagree with him about the answer being low quality. (Incidentally, I upvoted both the question and answer too because I think that it's useful information; in fact, I wondered the exact same thing when I initially read Moby-Dick in school).
IMHO, part of participating in Stack Exchange is that you have to be willing for other people to disagree with you without being outraged or taking it personally, so if the user in question couldn't do that they're not necessarily a good fit for the community in the first place. Because, guess what? No one is right 100% of the time, and there will always be people who disagree with you. Besides, if you think about it, the fact that someone disagreed with you online is a very first-world problem that's hardly catastrophic in the grand scheme of things.