The same could be said about the acronym BDSM, yet no one makes the same requests from those who use that to label threads and download links, and who assume that they don't need to explain it because it should be obvious what it means to anyone who lives in modern society. The term LGBT is used so frequently by news organizations and legislators as well as those "in the scene", and if it's not a part of common knowledge by now, it should be. It is considered the correct way of labelling it, after all.
Besides, anyone taking the time to read the descriptions of the books in this threads rather than just blindly download them, should be able to figure it out. And if not, the cover art usually gives pretty obvious hint... a picture of two men kissing each other can hardly be mistaken for anything other than what it is.
