It's the same argument anti-vaxers love to make. "Well you can still get covid after getting the shot", which is something I read and heard quite a lot. That doesn't make the thing useless.
Humans are really dumb.
This I'd an example of people not grasping simple probabilities. Forced to play Russian Roulette they prefer the revolver with 5 bullets in its chambers or the one with just a single bullet, because in both cases people die.
Other concepts many people do not grasp are feedback-loops and exponentials. And by not grasp I mean: You explain it to them, the nod along and when faced with the thing in slightly different clothes they will actively deny it'd existence.