You probably know from some
old threads that I agree with you on how the reg "should" be read. But take a look at
2010 Grayson - Must have CFI-I
I think you're familiar with it. The part that concerns me in the context of your comment is the first paragraph on the second page part that essentially says that a single-I can't give instrument training even for tasks for which there is no requirement for any training at all (the time in excess of the requirements that could just be with a private pilot safety pilot).
When the opinion first came out, I sent an email to the signer of the letter in which I expressed concerns that the interpretation in the letter was very broad and appeared to prohibit any instrument training beyond basic "flight by sole reference" to a student pilot; not even as much as giving a VFR pilot some extra skills in reading approach charts and flying an IAP for either emergency situations or simply to locate and get to an airport in marginal VFR conditions. I received a call from the person who actually wrote the opinion. The gist of our conversation was that the letter is intentionally broad and the FAA, as a general principle, doesn't want a one-I to give any "instrument training" at all, although he recognized there might be some exceptions here and there.