Sure the WINNERS are exceptional. They would be in any competition. The great part is that just preparing (practicing) makes people stronger problem solvers. Which is not the case in typical maths schoolwork.
To echo the parent, though: the school is NOT bragging about success on AMC contests. Probably because they do not have it.
Similar prep with a strong group of incoming students does work to produce successful AMC and AIME results, I can attest.
To be fair, I don't think your posts are making the distinction between A B and C.
I would say A and C are both reasonable. To get higher performance out of existing candidates, you would need a metric for performance... I am unfortunately not aware of one that is robust enough to be used.
To echo the parent, though: the school is NOT bragging about success on AMC contests. Probably because they do not have it.
Similar prep with a strong group of incoming students does work to produce successful AMC and AIME results, I can attest.