The actual treatment of why this mostly does not apply to maths is very thin.
And there actually is a problem with the notion of mathematical truth: Not within mathematics itself but in its transfer to sociological questions. Here, simply presupposing that concepts can be defined with a universal meaning and statements have a universal truth is simply not true. Mathematics is not advanced enough to discuss these matters properly. (So: New notions need to developed)
Since most readers here have a background in programming, here's an analogy of what the issues are: Sociology is about distributed systems. And these are more complicated. For example thinking about time in distributed systems requires quite a lot of non-trivial tech (vector clocks, etc). It's even more complicated for sociological notions.
But in general, I agree: The topic mostly does not apply to maths.