The whole performative bullshit about "assuming gender/pronouns" really ticks me off. Especially in this case where they are talking about some fluffy furball. Even if someone might complain that the alien got defaulted as "he", it's utterly retarded to ask it "what are your pronouns". A normal person will just ask whether it's male or female. Actually, they can just refer to it as "it" if they don't know whether those aliens even have males and females. Maybe they are all hermaphrodites. Or reproduce asexually. But who cares! The alien might not even know what pronouns are and what "he" or "she" stands for.
And if someone incorrectly refers to the alien as "he" but it actually isn't, a normal person's response would be "fluffy is actually a she" or whatever, instead of "did yoooouuuu assuuuuuuuume the proooonouuuuuns". You really have to be deliberately as obnoxious as possible if this is how you interact with people who do not obsess about pronouns.
Sorry for the sperg. I am just really annoyed to see these kind of performative, completely unrealistic, preachy interactions in current tv shows. (I haven't watched Doctor Who since Tennant left.)