Have you read the previous responses to this? Many folks don't feel included in LGBT. To not include them is harmful to the community as a whole.
There's nothing stopping folks from using LGBT as a tag, just like all tags they are up to the gamedevs to decide, this point was to make LGBTQIA and Queer tags visible to the community as a whole, as they don't even show up in partial searches.
It's impossible to include EVERY gender and sexuality in the specutrums in one acronym, but the closest we have right now is LGBTQIA because it at least attempts to cover as many as possible even under very broad definitions. This isn't counter-productive, there's nothing stopping LGBT from also being visible, especially for games that don't feature anything outside of that, but please don't make an assumption for the community as a whole without listening to their voices. And so far the voices have been in favour of this updating tags to make them visible.