The clue to the answer is in your own post. People say something is “ineffective”. What you have to say is that a) is ineffective in scenario 1. The problem is that people fail to understand this, and assume if something fails under 1) scenario it fails under all scenarios.
e.g.
Craig does Krav Maga, He knows that kicking men in the bollocks works. He knows because he has done it in training and in “the street”. Craig decides to become an MMA fighter. Three years later Craig has record on no wins, no losses, and 17 disqualifications. Craig cannot understand why he isn’t UFC Champ yet.
Or you have the opposite problem, where people think that because what they do works in there scenario, it is effective full stop.
e.g.
Billy is an MMA fan and trains at his local MMA gym. He knows that triangle chokes work. He knows this because he does them every week in training and his partners tap out. They work, he knows they work, end of conversation as far as Billy is concerned. Sarah is an SD instructor. She knows that if Billy tries to triangle choke someone out side the Chip Shop on a Friday night the guys mates will stomp Billy’s head flat.
Sarah explains therefore that whilst triangle chokes are effective in scenario a) (billy’s training) they are ineffective n scenario b) (outside the chip shop). Billy is unable to compute. He knows they work, he does them every week and his partners tap because they work. Therefore they will work in scenario a) all the way though to scenario z), and nothing Sarah or anyone else tells Billy will convince him otherwise.
Everything “works” and everything is effective, in the right context. But effectiveness can never be divorced from the criteria being used to judge its effectiveness. The problem is that some people cannot and will not ever understand that.