I read this and it really just looks like pedantic wankery for the purpose of showing off knowledge of modular arithmetic and set theory. I don't disagree that even in mathematics, context matters and there are nuances that usually aren't known or appreciated by people who haven't studied it in depth, but to imply that the sum of one and one is two is some kind of nebulous idea that is only true within a certain framework of biases is flat wrong and imo disingenuous of you. That is some hardcore "well akshualy" style pedantry.

Classical Greek mathematicians would have no idea what “1+1=2” is supposed to mean

Nonsense. Obviously they wouldn't have any idea what that specific set of symbols means because language. But the concept would absolutely make immediate sense to them. The fact that their mathematics was based on physical geometric relationships doesn't change this.

Making these kinds of claims doesn't help people understand how extremely context-dependent anthropological "knowledge" is. It does the opposite by implying that such knowledge is on a similar footing as mathematical knowledge.

Also, good job insulting Rev as being an incurious, shallow, uncreative "creature" for making a perfectly valid and reasonable point. Ugh.