Ok if you want to slice it like that, but to me that's semantics. Ellie's story is driven by her sexuality because that relationship is a same sex relationship. A lot of Ellie's plot and character goes away if Dina becomes a man. And the game does a lot to make sure the player is very much aware that Ellie is gay. Though I do find it interesting that they weren't willing to show two girls fucking, but were happy to show HERcules fucking her dumbass boycrush. Even a LBGT ally studio like Naughty Dog they still wouldn't go that far with the scenes. Ellie's sex scene is implied and Abby's is directly shown, there is even a few frams of Abby's Muscletitty but they wouldn't show anything of Dina or Ellie.
So that's why I link the relationship and sexuality together.
Sexuality even in games where relationships are possible, almost never use that as a plot point. The relationship stuff is almost always a side thing and optional. Like Mass Effect style games. This is likely due to the choices that the player can make across the entire cast, but still it does highlight that a characters sexuality shouldn't really be that important to overall things, because no matter who you love you deal with the same shit as everyone else. The LBGT stuff is the icing on the character cake, not the whole flavor.....if tha tmakes sense.
Look, I don't really have a horse in this race, but all of this just comes off as "gay characters are fine as long as there's nothing to indicate that they're gay."
Also:
-If Naughty Dog showed a hetrosexual couple having intercourse, but not a homosexual couple, that actually doesn't really paint ND in a good like. It suggests a double standard. Not necessarily, as I don't know the context, but...
-The whole "relationships are fine, sexuality isn't" comes off as semantics. You're right that many games have optional romance, but focusing on just those with built-in romance, the reason that het. pairings aren't considered sexualized is that het. pairings are the 'default.' Too many times, I've seen the complaint of "indoctrination" or "sexualization" for same sex pairings, but not opposite sex pairings. That's not to say that there aren't complaints about in-game romance being part of the plot, but it's not really the sexuality that's being criticized. For instance, using Overwatch as an example, I would bet actual money that if Tracer's romantic partner was named "Emile" rather than "Emily," then there wouldn't be the uproar of "the LGBT agenda" and Russia banning the comic in its territory, or someone from the Philipines asking me whether in the West, girls kissing on the lips is potentially a sign of non-romantic feeling (yes, this actually happened to me).
I know we've had this conversation before, but even as someone who's straight, I can see the double standard applied to romance in media here. To use a very recent example, it's telling that a number of people are threatening to boycott Lightyear for apparently featuring a lesbian kiss (and therefore, "the gay agenda"), yet were apparently fine with Pixar's very first film where Bo-Peep kisses Woody at the end. A LOT. Was that promoting a "straight agenda?"
Thing is, there actually are cases where people do look too hard for LGBT elements, even going against the author's own statements (take Luca), but even so, shippers gonna ship regardless. But overall, there's a level of scrutiny given towards same sex couples in fiction that opposite sex couples don't have to put up with. Not to the same extent at least.