Well if creators said that she is gay than i guess she is gay. So goodbye those theories about friendship kiss, bicurious incident, girls experimenting (altough all those suggestions are valid and real life because some girls experience them all the time) or bi/pan options. If Neil said she only likes girls, then she only likes girls. Heck, even Ellie's page on TLOU Wiki says that she is gay! Developers didn't make 180 turn and totally changed her character, they only added something that we didn't now, TLOU was pretty much tabula rasa regarding her sexual orientation so they had some solid fundations to explore that part of her in LB.
Altough i need to admit that i had a hard time coming to terms with this idea. First; I never thought about Ellie's orientation to be same as Bill's. I mean Bill is clearly gay, he had gay magasines and i think no one would argue that he is only interested in men. With Ellie...i dunno...i just have a hard time imagine her walking around Tommy's village, looking for her next girl or having lesbian magasines. And to just find someone of the same gender that loves you (in sexual way) in this post apocalyptic world when 60% of world's population is gone...that seems like a long shot.
And even altough Sam and Ellie were only friends (well Sam was probably having a crush on her), i never ruled out a possibility that they could have become something more, given time. Replaying LB unfortunately didn't change this view as much as i wanted it to. Plus i never got that that feeling that Ellie was looking at that poster with skinny girl in TLOU anyway differenty than she would if she was straight. And i also never got a feeling that she killed David's men in main campaign easier, because she has no feeling for males, or (like some put it) because she doesn't loves them.
Now this well sound very homophobic of me, and i'am sorry for that and apologise but in real life i have a lot of gay/lesbian friends. I could spot someone is homosexual from a mile away (the way they interact, behave, sometimes even dress). But with Ellie i just don't get that vibe. She is just so not that stereotypical gay character that we see in media these days, and maybe she was even written that way. But if there was no controversial kiss, i would have never know.
I admit that i was one of those that hoped she would start a family, have her own biological children to spread her immunity. So that her "gift" wasn't just a giant waste. Well...that went out of the window.
Even when i was playing LB i thought that Ellie kissing Riley was something natural because to her, Riley was the only person that ever cared about her. I mean she stole those water guns form general Dickhead (or from somewhere/someone else), traversed entire town full of soldiers and gave up her dreams of becoming a Firefly just to be with Ellie. I'll go on a limb here: i am straight male that loves girls VERY much, but if i grew up in their world, with no family, no special love or care, little to no friends and then met some boy that would do all those things for me that Riley did for Ellie...well shit i would have probably kissed him as well. But that is just me.
BUT Druckmann already confirmed that she and Riley are gay, so all my previous statements are invalid. She is gay, and we all have to deal with it.
As for the future; even if they make Ellie reappear in TLOU 2 (if there is a TLOU 2), they will never make her to be in a relationship, because they think that is unimportant. They will never make so that Ellie would have a boyfriend because they said that she is gay + making her having a male partner would feel like something of a fan service, not a real life thing. In the end all we can do is to accept that she is gay. Like we need to accept star wars prequel trilogy or matrix 2 or 3. that's just the way it is.