3) 2+2=5 highlights that math has a cultural aspect in choosing definitions/conventions, selecting and bundling ideas, communicating them, etc.
https://www.mathvalues.org/masterblog/of-course-2-2-4-is-cultural-that-doesnt-mean-the-sum-could-be-anything-else
https://twitter.com/kareem_carr/status/1290351418621210624?s=20

Once chosen, the deductive and symbolic part of math is fairly neutral. Cool.

4) The fact that math has a cultural aspect and is often done with others means there's room for human biases and discrimination in math as a profession and in math education. E.g…

https://www.nytimes.com/2019/02/18/us/edray-goins-black-mathematicians.html

https://files.eric.ed.gov/fulltext/EJ1199792.pdf

5) These issues of bias and discrimination raise the question of curriculum. What belongs? What doesn’t? This is wildly complicated and goes to the heart of the question: What is (math) education for?

Anyone who has a simple answer is either wrong or deserves a Nobel Prize.

6) CJ: Postmodernism will burn the world to the ground

Response: https://twitter.com/katja_thieme/status/1290760621575639040?s=21

Fact: Embedding the mathematics and experiences of Yup’ik elders and teachers into math lessons led to improvements in the math performance of Alaskan students http://asdn.org/wp-content/uploads/Ethnomathematics-Applied-to-Classrooms-in-Alaska-Math-in-a-Cultural-Context.pdf

7) Bringing up 2+2=5 isn’t an attack on math, logic, bridges, spaceships, or civilization.

People are still trying to figure out how a critical view of math should translate into classroom practice. That’s OK.

Not OK: Missing the point and harassing people in the process.