It's not much more than this that is being requested. An acknowledgement of alternate sixualities, but without it being a joke, a crude come-on or a comedic stereotype. Fallout 3 had at least one reference, and fairly subtle. New Vegas has at least one companion who tells you she's gay in conversation, but nothing really more than that.
It's really not much to ask of Bethesda. Of course, they'd have to do a slightly better job of including any kind of relationships among NPCs first.
edit: I'll admit to a slight ulterior motive here. I'd kinda like to see it included so that some pathetic bigots can freak out about it and then refuse to play what will likely be a great game. Serve them right.
I counted 4 people in New Vegas who where Homosixual/lisbian
Arcade Gannon
Major Knight
Veronica
Cass (although she did not care who she slept with)
All revealed in conversation.
Oh and Ceaser's Legion is more supportive of Homosixuality, and most would rather sleep with each other than the baby momma's and slave girls.http://fallout.wikia.com/wiki/Confirmed_Bachelorhttp://fallout.wikia.com/wiki/Cherchez_La_Femme with the same six.
(just so you can add more to the list)