Fair enough!
When I was in US public school in the 60s and 70s, the science teachers taught us about Volta and Galvani, and we dissected frogs (prior eras vivisected them, but thankfully that was phased out the year before I took the class) and made their legs jump with a battery. They also showed us colorful pictures of human innards including the nervous system(s) and spinal column. I guess I just thought everybody born in the USA after 1945 got that level of education, which was narrow-minded of me. 
In my own experience TENS and chiro are both very effective for very specific problems. Neither one is a substitute for antibiotics, a healthy diet, sane exercise regimen, &etc.*, nor are they fake medicine**; they are cost-effective evidence based treatments.
* Despite claims by crackpot practitioners and religions.
** Despite claims by corporate pill-pushers and pseudo-scientists.
