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 n

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?