Math should not come with any subjectivity or ideologies period. It is discovered not invented. It is true regardless of the bullshit ideas we have cooking up in our mind.
I would describe this as a half-truth. The statement that math is discovered and not invented has value, especially when given to a high school student who is under the mistaken impression that mathematical rules are made up and don't make sense. However, that doesn't lead to the notion that math should not come with any subjectivity or is true regardless of the "bullshit" ideas we have cooking up in our mind.
When I was in 3rd year algebra, one of my assignments was to prove a theorem that was a consequence of the Fundamental Theorem of Arithmetic (which states that prime factorization is unique up to order.) I was the only person in the class to (correctly) state that the theorem wasn't true. Why? Because the text we were using had used a slightly peculiar definition of prime numbers, which included negatives. Under that definition, the FTA isn't true, and so neither was the assigned theorem. So was the definition wrong? Not precisely. The justification for using it was that it brought the definition of prime in line with another concept known as irreducible, and so it had a certain advantage. This kind of thing isn't that unusual by the way; often if you look carefully at university-level text books, they use slightly different definitions of concepts, and sometimes even subtle differences can have far-reaching consequences. The point being that the definition
mattered, and so in math the correctness of particular conclusions actually depends on the constructions that we establish. You always have to take
something as axiomatic, and rethinking those axioms can be very significant.
Is the sum of the interior angles in a triangle always 180 degrees? Many people would instantly take this as an absolute, but it isn't exactly true to say this statement holds. It does in Euclidean geometry, but it doesn't in non-Euclidean geometry. In essence then it is a consequence of the parallel postulate, and when that axiom is no longer taken, the truth of the statement changes. In other words, mathematical truth can be contextual. Non-Euclidean geometry is, of course, not only entirely valid, but essential to our understanding of how the universe works.
I studied the history of mathematics, and there can be a lot of value in understanding how different cultures approach the subject. Pythagorean Theorem is a great example. An enormous variety of proofs have emerged from different places in the world, and in general being able to see different ways of arriving at conclusions can be very instructive. But there are some interesting historical questions surrounding this also, such as the
philosophical attachments to the theorem (and Pythagoreanism generally). Or why we refer to it as the Pythagorean Theorem in the first place? This is not necessarily sinister, but it's worth asking the question when Pythagoras was absolutely
not the first person to establish the relationship.
Where you really can't divorce math from subjectivity is in its application. Certain results drawn from a mathematical model might be objective, but whether or not that model effectively represents a real-word situation, or how to interpret those results, is rarely so clear-cut. I've seen plenty of situations where people did some calculations correctly but ultimately drew (in my view) the wrong conclusions in the way they interpreted their results. Statistics is a mathematical discipline dripping with this.
I don't think any reasonable person is going to argue that if one student gets an answer of 6, and the answer is actually 4, then we should somehow give the student the impression their solution is equally valid. That's not what's being discussed. The point is that even mathematical truth isn't
quite as simple as it's often made out to be, that the historical and cultural context of mathematical study is significant, and that the application and interpretation of math cannot be so easily separated from a person's point of view. Personally, I do think it would be wise for math education to pay more attention to these things.
Which is not to say that I necessarily agree with everything the government is doing here. Firstly, the curriculum is not the end-all be-all of education. How the subject actually gets taught in practice is much more complicated, so the jury's still out on a lot of this. Destreaming grade 9 might have some benefits (and some negative consequences too), but I also think it's roughly equivalent to saying you can get rid of a problem by pretending it doesn't exist. The reality is that students have had radically different experiences in their education long before then, whether it's officially recognized or not. Destreaming grade 9 is not going to change the fact that many students are not put in a position to succeed at that level. My experience suggests that this problem may be aggravated by aspects of identity such as ethnicity and gender, but it is still universal. If a student has had a lacklustre math education prior to grade 9, it's extremely difficult to make an effective difference at that point. There are systemic issues at a lower level that desperately need to be addressed.