alt Hacker NewsPsychologists call this black or white thinking - in this case, either something works perfectly or it's useless.
Next to impossible to get a person who believes this that they're engaging in a cognitive distortion though. I tried the same thing you're doing, once. I gave up. They will die on this hill and then wonder why they lost long after everyone else had moved on.
It's possible to make effective arguments in line with their values. They simply don't want to be helped.
> Psychologists call this black or white thinking
The same can be told for your thinking. You (and several other posters) lumped several arguments into the same Nirvana fallacy [1]:
1. It's not 100% effective
2. It's only 50% effective
3. It is not even 10% effective
These are very different from each other. The first one may actually mean what you described (either something works perfectly or it's useless) but the others must be discussed separately.
[1] https://en.wikipedia.org/wiki/Nirvana_fallacy