That's the Divide et Impera -principle. Divide and conquer. The term "useful fools" was coined by Soviet regime that used it very effectively, by finding a group of sufficiently ignorant people who were scared stiff of losing their specific rights who wouldn't shun throwing their peers (of somewhat different interests) under a bus, and using them as a propaganda tool to exclaim "what people want".
Beware them. They're effectively traitors who really think that by parroting the regime narrative they'd be entitled to preserving their status, which eventually never happens. Eveyone lost everything. They're every bit as bad as prohibitionists, often even worse as they have propaganda value to the regime in terms of silencing all opposition to totalitarian legislation.
These useful idiots contributed greatly to gun laws in Finland going to utter $#!% between 2008 and 2019. The left wing forces in the government tried their best (worst) between 1999 and 2008 but got nowhere until they managed to turn some "fudds" against all other gun owners and launching a relentless propaganda campaign that these groups represent "pro gun" side of the debate. Effectively silencing and deplatforming anyone else.
Treason. At its very worst.
