I appreciate that you want to do right by your children. I'm glad you wound up with a better situation under conditions of misdiagnosis. When medication is clearly unnecessary, I agree that better not to.
But it is not true to say that every single case is the same.
Making universal statements about the nature of ADHD and universal statements about available treatments can deter people from seeking and receiving help that would work for them.
Experts are more likely to diagnose correctly than layfolk. No single error changes that fact. Insofar as people are deterred from seeking expert attention, the net effect is harmful.
Attributing the differences in our experiences to a uniform medical conspiracy against the public doesn't bear on whether treatments work or not for different cases.
My parents cared too. Nobody told them about ADHD, because it just wasn't a commonly-known thing in that time and place. I was smart enough to stumble forward through school, with their love and heartbreak and the dedication of many frustrated teachers. But I would've done a lot better with just a little treatment. And I find it hard not to take personally the idea that others should be discouraged from seeking help from a professional.