Call to turn exam failure into a qualified success.
I fail to understand the mindset of these people. Or, rather, I fear that I understand it quite well, but that they would not concur with my understanding of it.
There is a kind of practical wisdom in “if at first you don’t succeed, try, try and try again” - it’s what keeps me going back to introductory papers on Category Theory (say), in the hope that this time the things I’ve learned since last time will give me sufficient traction to progress. In practice, this has worked out for me sufficiently often that I have the confidence to keep hacking away at certain things that I find difficult. Instilling that kind of confidence in pupils is a legitimate educational goal. But it comes from learning to experience failure in a particular way: to recognise it, determine its causes (“this paper was opaque to me because some of the basic concepts it assumes familiarity with were unfamiliar to me; I need to familiarise myself with those concepts if I am to make progress here”), and estimate the likely costs of trying to overcome those causes (“is it really worth my while to put in the hours needed to cover all the prerequisite background reading for this?”).
Failure is not simply deferred success, because getting from failure to success is more than simply a matter of time (or continued unmodified effort). If you fail at something, and it isn’t a matter of straightforward bad luck, then the chances are that it’s because you’re doing something wrong. You need metacognition - rational self-appraisal - to correct the mistake and continue; and it’s always possible that rational self-appraisal will lead you to the conclusion that you don’t have a real chance of success and should simply try something else instead.
Young children are not innately skilled at rational self-appraisal, but it seems to me that it is taking something important away from them to refuse even to recognise their attempts at forming judgements of that kind. There is indeed some such word as “can’t”, and one needs to learn how to use it effectively. If a pupil says, “I’m hopeless at this; I’ll never succeed”, then it’s worth considering the possibility that they might have a point, even if it’s also important to encourage them to consider all the angles and look at ways of proceeding that they might not have considered.