No, it's more like claiming a regular whistle contains an additional imperceptibly high frequency, with the intent of trolling progressive people into confusing

No, it's more like claiming a regular whistle contains an additional imperceptibly high frequency, with the intent of trolling progressive people into confusing legitimately ordinary whistles for dog whistles. In far-right internet communities, these sorts of troll-whistles are concocted all the time for their own amusement and to sow discord and backlash. The true dog whistles are the private, opaque lingo they use among themselves. Sometimes these troll-whistles do grow to become actual dog whistles once news and social media take the bait for a while, but that's only because their manipulation game successfully worked. They're constantly trying to see how far they can push it. They exploit the ability to make something taboo purely through light astroturfing and propaganda work. The current political climate makes it very easy. I sometimes find myself identifying real dog whistles and getting accused by one side of paranoia for pointing it out (until I provide detailed sources explaining the terminology), and identifying troll-whistles and getting accused by the other side of apologism for saying they've gotten played by trolls.