Let me start out by telling a little story about an experience I had with a similar issue. Years ago I was in charge of doing the book displays at my branch library. It was February and I decided to have Black History Month display featuring mostly fiction works written by African Americans. I live in a slightly backwards and almost completely white town. That being said, one of my co-workers was very upset with my choice of display and said that if I wanted to have a Black History Month display then I should also have a display for every other race. I told her I would be more than happy to do a display for National Hispanic Month and so forth, but there isn't a national month for Caucasians and that most of my other displays already prominently feature white authors. We never really came to an agreement, but because she was not my supervisor (who had approved the display), I kept it up. The books didn't have a large circulation but that was beside the point. I felt it was necessary to display acceptance and equality in a public library because that is what we stand for- freedom.
As for whether I would create a separate section for LGBTQ and African American books, I don't think I would make a permanent location of either of them. I would do the same thing I did above; I would dedicate a display during Black History or Gay Pride. While it is important to highlight these topics, I don't want to divide them from the rest of the collection. That is creating a segregation of sorts in the library stacks. The library is essentially saying these books are different than the others and must be kept separate. Also, the patrons may feel targeted if they are browsing a section of just LGBTQ books. I also agree with the idea that it "disrupts serendipitous
discovery of an author who might be different from the reader;" we want people to browse and expand their reading horizons.