While I understand the issues with alternative medicine quackery, MTHFR is an interesting biomarker in mental health and the use of methylfolate in inadequate responders to SSRI medication is evidence based. https://pubmed.ncbi.nlm.nih.gov/34794190/

Are you only suggesting that commercially available genetic testing remove MTHFR C677T and A1298C? Or are you suggesting that it be removed from pharmacogenomics panels as well?

A second, more philosophical question would be, why stop people from having the data? Methyltransferases are ubiquitous, and it is an interesting entry point into folate-mediated one carbon metabolism. FOCM has a number of uses, like controlling epigenetics (DNMT), creating DNA (via Pyrimidine), phosphatidylcholine (via PEMT), and creating neurotransmitters (via BH4 and COMT). Knowing the issues with the biochemical system is interesting, and MTHFR is a very old and well studied set of polymorphisms. Dr. Nijhout & Reed at Duke even have a full computational enzyme kinematic model of FOCM. You'll have quacks regardless of what actual data you provide. Why does removing the MTHFR polymorphism from 23andMe provide any benefit? Save for preventing unnecessary blood draws for hyperhomocystinuria testing and preventing people from asking doctors about their lack of up-to-date biochemical or genomic knowledge.