Fact is these devices are not illegal because they can run retro games. What is illegal is selling them with the games inside.
If the batteries were not legally compliant, that’s a whole different matter. But the article puts the focus on how they could play “licensed” games and were illegal when that’s a blatant lie. These consoles are completely legal (from a copyright standpoint) if they are sold without any games and you then get the games by yourself.