There's nothing new or degenerative about ethnomathematics, really. It's simply acknowledging that different cultures - especially due to common language - handle math and numbers differently. The Chinese language, for example, articulates numbers way differently than English. In English, we say for 18,210: Eighteen thousand two hundred ten. This is very efficient but doesn't generate potentially beneficial neural pathways forcing the brain to effectively add every time you articulate that number (or one like it) as does articulating the same number in any form of the Chinese languages, for example. In Chinese you might process this number in your head as: one ten thousand eight one thousand two one hundred one ten. That language literally builds the number in its articulation and consequently you may be able to do "head math" more effectively.
Part of learning math is your parents (or your self-drive... rare) sitting your tiny ass at the dining room table and hitting the books for hours until it clicks. For some students, they simply do not have the wiring for advanced math to click regardless of determination or time spent studying. But, for most human beings, enough dedication and studying will get you through Calculus, which IMO every single student should be required to take in this country before being awarded a high school diploma. I'm so sick of students getting degrees and avoiding all but "College Prep Algebra" (unless that same school offers trade education).
For me to learn math, I have to understand the why and how of the equation. Not just follow the steps. I have to know why the steps are the way they are so that I can extrapolate and apply to a different scenario that is supposed to use the same methodology (and be able to see that that methodology is what is needed). Many, many teachers do not teach the roots, just the flower. And unless the student has a natural proclivity to math, he/she may never be able to truly understand the equation or purpose of the equation. Consequently, even if they manage a good grade, they do not retain it and they cannot actually build from it (especially after a summer of zero academic rigor or application of that knowledge in real world scenarios). Some students - like me - actually fair better skipping introductory classes and being forced to back-learn/reverse engineer from a more complex scenario. Some students require significant effort toward critical thinking - not just explaining the answer but getting them to think through the process and why the answer is correct (or not). The latter is a form of what I think is being proposed here (and also an effective tool used to teach children with learning disabilities of varying types and degrees).
That said, there is not "more than one answer" to most math scenarios, especially those taught in anything less than a PhD in Astrophysics. Unless I'm just missing something, 2+2 is 4. 7 x 3 is 21. 20 / 4 is 5. There's many ways to think about how to do that equation... but it's always one answer. This approach, as far as I can tell from these horseshit articles on it, would seemingly confuse children more than help them.
White people did not create math. It's rooted in the Middle East. We have Arabic numerals. The Sumerians created the first crude procedural form of it (of course for the purpose of taxation) using the bones on the 4 fingers (not thumb) of each hand. Even today in West Africa, many people articulate and think about numbers as numerals of 5 or 20 aligned to the number of digits on a hand or total number of fingers/toes. Cultures have thought about numbers differently ever since. The way children in the US are taught math is inferior to Germany, Japan, China, Israel... the list goes on. I'm all for change in STEM teaching. I'm not keen on doing so because the existing approach is "racist"... that's a lot. That feels akin to saying the standard way of writing music is racist because a black person and a white person might play the same song from the same sheet differently. When it is in fact the case that two white people of equal skill but different emotional conviction will play it differently, too. But that is the application of the answer to the math equation, not the answer to the math equation. When it says "play C#"... you play C#. You may hit the note harder or softer, cut it just a billsecond sooner, let the string hit the frets, whatever... but you are playing C#. That C# is math. You can do whatever you want with the instruction beyond the baseline of it having to be C#.