That being said, I would be surprised if you could find an example of anyone at all prominent or influential on the left expressing in writing the position that you quote.
How about this for a prominent and influential source:
https://www.nature.com/articles/d41586-019-00677-x
The headline is "Neurosexism: the myth that men and women have different brains"
Under the sub-heading "Cultural paths":
"So if it’s not brain hard-wiring, how do we explain the often stark differences in behaviour and interests between men and women? Here is where we get to Rippon’s thesis on the impact of a gendered world on the human brain."
You can inject people with testosterone and estrogen and observe behavioral changes (as people attest to in this very thread), so it's certainly a pretty strange position to have. Neuroscience is too important for these nonfactual statements to be accepted, let alone be published in Nature. There's a pretty thorough counter argument here: https://quillette.com/2019/03/29/denying-the-neuroscience-of...
The brain is a bit of a red herring here. We know little about the brain -- far too little to be able to draw any conclusions from whatever differences there may be between average male and female brains. We do, however, have reliable behavioral evidence of small cognitive differences between men and women on average. My point was that there are few if any people who deny the existence of such differences.
I can't leave links to my life experiences, but as I finish my undergrad I have heard every type of teacher and student maintain that the only differences between men and women are socially constructed. It is common knowledge and thus not really debated. The one time I saw a teacher maintain otherwise, it was a guy in the biology department who was retiring. The class session dissolved into a shouting match between students with the teacher looking on.
I suspect that you weren't listening very carefully to what people were actually saying.
This isn't a problem, though. This is probably what happens when it turns out the Russian bogeyman was just a fever dream. Indeed, being in a public University in the North East as well as 2 of my 3 concentrations being in the liberal arts, I'm quite used to people ignoring actual fires as they continuously harangue everyone about potential fires.
I cannot see any connection between the second paragraph of your comment and what we're talking about.
If sex-linked behavioral changes at explainable by hormone differences and can reproduced by in vivo manipulation of hormone levels, that supports rather than refutes the idea that intrinsic brain differences are not responsible for the differences.
In any case, though, the article does not support the upthread claims of either a view that there are no sex differences in mentality or that there are no physically-based differences in behavior, and all are social, because it addresses not behavior or mentality but brains.