We've had a pretty popular kids coding app in the App Store for about 6 years now (Kodable). We've never remotely considered having ads and never will, and from the article it sounds like this heavily skews towards the ad-heavy Google Play store.
From my experience most of the big name kids app developers do not put ads in their apps (almost never on iOS), although I can understand why developers do.
Whether you like it or not, they work. There are two things that are always going to be true about this - kids are going to download lots of free apps (because it is easier than asking parents to pay), and they are going to accidentally tap on ads. The developer doesn't care if the user will actually purchase the product being advertised, all they care about is the click. That's just the way PPC advertising incentivizes developers. The only way around this is strictly limiting advertising for games targeting children. That has to come from the App Store moderators (Google, Apple, etc).