Cuz if you read the "+" definition, you'll see it only including sexuality from human-to-human perspective.
The rest has nothing to do with it or is at least something completly different from the definition.
He's actually not wrong though. Even if it's pretty ludicrous.
In a few decades, nobody is going to say "wow, we have a gay character in a game" in the same way that nobody says, "wow, a black guy is a professional athlete!" But until that time comes, people on both sides are going to make a deal about it, and I think that's an appropriate response.
You aren't wrong. Sadly.
It would be great if people stopped nitpicking at small descriptors.
Sexuality is but a minor characteristic of an individual, not the entire individual itself.