I think it may be that they hear these descriptions of ECs-- because it’s the kind of thing everyone talks about – without hearing “excellent grades and scores are table stakes”.
It doesn’t help that many parents are coming from a time when a top GPA and excellent SAT score was, in fact, outstanding enough that with that alone and perhaps an EC or sport, the odds of admission to a very selective school weren’t bad at all. It’s all a decoupage of scraps of info, not pulled together into something coherent and accurate.