I wouldn’t focus on whether it’s “identifying” but whether it’s revealing. Young teenagers are a very high-value target for advertisers. They are very impressionable, and they provide a proxy for advertisers for their parents’ money. So this law essentially makes it mandatory to share that information with advertisers. And also by proxy, predators.
It also makes it explicitly illegal to do use it for such purposes. While I agree on the point, I think in practice it changes little. I also think it could be a net positive, because now there’s no plausible deniability about the targets age, opening up a decent amount of liability for exploitative practices targeting children specifically.