Perhaps he is relating personal experience with his own parents. There are such., all the ones I know, though, crave to see their children do better and know more than heir parents. “She/he is so smart, I don’t know where he/she gets it!” proudly spoken.
Your point of view is similar to my thinking.
A dumb kid is in essence a reflection of their parents, and no parent really wants that.
Both our kids are quite smart, and I was once told they inherited it. Thus having a smart kid is a pat on the back.