Conjecture? Perhaps, but it does get at the what I am talking about which is people equating passing the JLPT with being proficient in Japanese
I have still to meet the person, who thinks passing the JLPT says much about the proficiency in the language. Most that I meet who take it, are alot more critical towards it. Seems you meet other people than I do. Maybe I should add I am not in the US, but test taking is the same all over the world I guess. No test really prepares for reality, I am pretty sure, in no field at all. Though some tests are certainly doing better than others.
JLPT is for me just one of the "guidelines" to study the different areas asked in the test, so to speak. I do not learn Kanji for a test, for example, but since I have to follow *some* order, why not take the JLPT one. Same goes with grammar, I do not learn it for the JLPT, but since it so happens, that Minna no Nihongo I was about the scope of JLPT4, why not take it. Same now with MnNII and JLPT3. Does the test make me better at anything, apart of test taking? No. Does learning grammar, kanji etc. enhance my proficiency in the language? I certainly hope so. It is not like the test is different from actual language skills (at least at my level), it is just a limited selection of what proficiency in the language is.
If it is not for you, good for you. If one has fun taking tests, why not do it.