Probably because it's possible for people to implement these sort of weapons, and they don't want terrible people inflicting somewhat untraceable brain damage on unsuspecting victims, seemingly out of the blue.

If they're leaving out explicit (or even the vaguest) details, it probably means that's the only thing keeping this out of the hands of weirdos.

Also, other layers of secrecy are likely in play. It's probably already known that such weapons do exactly these things, but how would people even know, without published research? Top secret military experiments? Private research performed by military contractors? (in other words, takes one to know one)