To confused people exploring from all Communities trying to understand what the hell is going on:
Bethesda is a game studio who does a decent job of giving people choice to do/be whatever they want in their games. Out of the box they included the option to choose your pronouns in a new game called "Starfield".
They also make it possible to modify their games to make very drastic changes to the player experience.
Nexus is a site that hosts thousands of mods to all sorts of games. People make mods, upload them to Nexus and players download them.
Someone made a mod to remove the option to choose pronouns from Starfield.
Nexus decided they don't want to host this mod. It's hurtful to people and goes against their values of inclusivity.
That's about it. Most of the people whinging about censorship don't even play the game. They're just here to whinge about how the world is moving on from old bigoted ways and they want to stay in the past and be jerks to people for merely existing. If they actually cared, they'd just download the mod from some other site. The mod itself is probably not much bigger than this reply.
I'll add that my understanding is that you aren't even prompted to choose a pronoun in-game -- it defaults to one or the other based on your character creation choices, and you can then change it if you want to. It's literally a non-issue.