Judging by the fact that most maths degrees are listed as science degrees, it's pretty clear that "mathematics is not science" is a controversial claim.
I don't think that's true. Certainly among the people in my department while I was doing my PhD in mathematics, it was universally agreed that mathematics is not a science (because mathematicians don't do experiments as a part of their work).
Even outside of math departments I see some evidence of that agreement -- for example, why else would the "STEM" acronym list Science and Math separately?
> Judging by the fact that most maths degrees are listed as science degrees
How colleges categorize their departments has an element of politics to it, so I wouldn't pay much attention to that. I've got both a math and science degree, and none of my professors or peers would consider math to be part of science -- even considering our math department was listed under our science department. I think OP is correct that this topic is not controversial at all, at least among the people who actually do math and do science. There's no question that math and science are completely separate things.
Judging by the fact that most maths degrees are listed as science degrees, it's pretty clear that "mathematics is not science" is a controversial claim.