The neutral-Blocker is what our poco calls it, it isolates the primary-neutral from the secondary neutral.
No the poco does not disconnect their grounding, this site from what I can figure out is trying to sell something, with the idea that stray voltage is the fault of the power company. When I read this I was livid. and of course a 'slick-talking salesman' is going to place all the blame on the poco.
They even bash equi-potential planes as being too expensive and not that effective. Which is only partially true. So Armed with a pocket-full of half-truths these people are making a living.
The trouble is farms are seldom bothered by the local AHJ.