It actually is for (most) mammals, so I don't understand why this must be a far-right sentiment. "toxic masculinity" aside, one of testosterone's effects is to grow muscle.
Right is explained with nurture, then biological facts have more weight in their explanations.
Left is explained with culture, then cultural facts have more weight.
Anti-femenism, anti-gay, racism, competitiveness... all are explained with biological facts.
If you are making the distinction of "biology" vs. "sociology" then the biological side is commonly referred to as "nature."