Not just any elf-children, but children of the Noldor. And not just any Noldor, but the scene implies that many of them are from the House of Fëanor. Who are the biggest assholes in the history of Middle-earth. The Silmarillion is largely a story of that.

The series has many issues, but the showrunners not understanding the works of Tolkien is not one of them. Many of the issues arise from the main premise of the series. Like with many recent big-budget adaptations, the showrunners are retelling the story from the perspective of a subset of 21st century Americans. If you are not in the target audience, many things may feel off.

Also, it's good to remember that big-budget adaptations usually fail. Any story worth adapting is likely exceptional. Because you are retelling the story in a new format, you usually have to change many things. But the new things you create are unlikely to be exceptional, because exceptional things are rare.