Obviously they are wrong, but I don't 100% blame them.
Our education system still hangs on to the idea of competitive testing. It is still structurally present throughout our education, so its hard to blame parents for viewing the whole thing as a competition where any advantage given to one child is an advantage taken form another. A zero sum game etc.
Education research + theory has moved past this, and the ideas around the purpose of standardized testing have shifted far from 'competition'. We now aim to prepare children for future life and to contribute to society - which means preparing them for a world which will usually accommodate their individual needs. This is another backwards thing that you will hear "In the real world, no one will give you special treatment!" Yes, in a lot of situations, they will. And not just because it is required, but because it makes business sense. Why would you place fixed restrictions that limit the talent and ability of your workforce by not ensuring that each can perform to their best? More and more companies are realizing this, thankfully.
Generally life, work, business etc. All center around you being able to find a way to show your best ability. Not whether you can do exactly the same task better or worse than someone else, under exactly identical conditions.
But our education system still holds on to these outdated views, they are parroted by politicians who have no education in education, newspapers, journalists etc. and then filter down to parents who don't know better.
So they are wrong, but I can't 100% blame them, because they are just trying to play a system, and the system is still somewhat wrong.