They are obviously dangerous, but they have practical use for solar and generators. I wouldn't be surprised if this is part of the push to stop plug-in solar.
Those are called suicide cords for a reason. Exposed prongs is only one problem: another is that these can end up feeding current into a line that was supposed to be de-energized, potentially killing a lineman (I also wanted to add that they can short-circuit between phases, but then released that's only a problem for Schuko, not NEMA). If you want to use a local generator, install a generator transfer switch.