Nintendo has not explained their reasoning. The Sony PS5 is in the same situation though, with a hidden kind-of usable Internet browser. Both systems also have M-rated games, YouTube, Hulu, Twitch, other streaming apps, and parental controls to manage them, so I don't think it's about user age. It could be a platform security decision, as the Wii, Wii U, DS, and 3DS all have had browser exploits. Although, since the Switch does have a browser still, it's also still vulnerable regardless of it being accessible to the user or not.