I agree that gender is a social construct. So is sex. (So is the other kind of sex.) So is species. So is “fish”. So is blue. So is reality.
People say “X is a social construct” as though this were some deep, profound statement about this thing being actually some form of mass delusion.
All “socially constructed” really means is that the definition of a word–or concept–is agreed upon via some form of common consensus. Thus, the meaning of words can be changed if everyone decides to do so.
“Gay” was once socially constructed to mean “happy.” Now, by popular consensus, “gay” means something else. Back in the ’60s and ’70s, homosexuality and pedophilia were conceptually linked–we would say, homosexuality was socially constructed to include pedophilia. Today, the two terms are not seen as synonymous–the social construction has changed.
You ever notice that “red onions” are purple? Our socially constructed categories of “red” and “purple” have changed.
We all filter the raw material data of reality through the ideas, concepts, patterns, and categories already in our heads–our assumptions about the world can lead two different people to have radically different experiences of the exact same physical reality.
This is a natural effect of language being language, rather than, say, rocks. It is not a profound statement. It is a caution that we may be led astray at times by conceptual categories, our categories/definitions may need occasional updating in light of new data, or that edge cases may not always fit neatly into broad categories.
Most people understand this intuitively, as part of how interfacing between our fallible little selves and reality works. That reality does not always conform exactly to our notions about it is confirmed every time we stub a toe.
When people start making a big deal out of social constructivism, it is natural to think this must be some big, profound, important insight, otherwise they wouldn’t be going on for so long.
But people only pull out this argument when they want to deny the existence of actual reality, not when trying to argue that your notion of “ornamental shrub” is socially constructed and you should plant a blueberry bush.
Reality exists, no matter how we care to conceptualize it and organize the data we’re getting about it. Most categories that weren’t invented for the sake of a novel (“elves” probably are totally made up,) exist because they serve some sort of functional purpose. Being able to call someone “male” or “female,” “black” or “white” or “Bantu” or “Japanese” allows me to convey a bundle of information to the listener–a feature of language obvious to virtually everyone who has ever engaged in conversation, except to folks trying to eliminate such words from the language on the grounds that they are made up and so carry no information.