Stop. Right. There.
Where do they get this "unequivocally false"? That sounds like they think they have something "purely objective" in... sociology, maybe? They're using their "purely objective" sociology to judge the objectivity of math, and finding math to be non-objective.
That's insane. These people should be barred from math and sociology.
In sociology, you got the replicability crisis (aka, it's mostly bulkshit).
The Sociologists want to bring that to mathematics so that the marginalized of the world don't feel inferior.
See also: https://www.quetzalec.com/
relevant sample:
"While some mathematical skills and concepts build off each other, the forced construct of linear teaching reinforces objectivity. A prime example is how matrices is considered a precalculus standard, even though the only math skill needed as a prerequisite is arithmetic. This is highly detrimental to students because they are systematically deprived of knowledge they could access due to false constructs. Math teachers have internalized the sequences that have been predetermined by standards and textbooks, rather than sequencing learning based on (pre)requisite knowledge. In general, teachers teach math like a ladder rather than a web."
>The framework recommends eight times that teachers use a troubling document, “A Pathway to Equitable Math Instruction: Dismantling Racism in Mathematics Instruction.” This manual claims that teachers addressing students’ mistakes forthrightly is a form of white supremacy. It sets forth indicators of “white supremacy culture in the mathematics classroom,” including a focus on “getting the right answer,” teaching math in a “linear fashion,” requiring students to “show their work” and grading them on demonstrated knowledge of the subject matter. “The concept of mathematics being purely objective is unequivocally false,” the manual explains. “Upholding the idea that there are always right and wrong answers perpetuates ‘objectivity.’ ” Apparently, that’s also racist.