I believe part of the post is referring to that idea (self disclosure and weirdness) itself, and the idea that the author usually does try to limit it. Even without this specific post, the "weirdness" can come across in an in-person interview and other ways. Some people are normal, some can pretend to be, and others either can't manage to pretend or its too difficult/painful to do for long periods of time.

Its not always bad to expose it and not always bad to get rejected because of it. Personality mismatch can make any job miserable.

Regardless, it feels bad to get rejected and that, I think, is what the article is making a point about.