I'm sure at some point people will be advocating that kids who do better at math be given shots of whisky until their performance is at par with other kids.
You could get extra help after school. Should a teacher just move as fast as the best student? You seem to want the education system to mirror capitalism which I find morally reprehensible.
What if you can't get extra help, what if that's not enough? A child doesn't have that much control over their lives, who knows what is going on at home. Maybe class is all they have.
You're right about my interpretation as black and white. I still think it's an issue if some or even one child (assuming they don't have some mental issue) is left behind in a class. Meaning that the teacher won't slow down for one child but the pace is acceptable for everyone.
We are not, should not, and cannot all be the same.
I am bad at languages. Should I now demand that everybody please slow down so that I do not have to feel bad about myself? ... Nope.