Nintendo has recently updated the end user licensing agreement (EULA) for the Wii U. This is a normal occurrence.
The difference this time, as the Electronic Frontier Foundation pointed out in this article, is that if you choose not to agree, you don't just forfeit some functionality, you are completely locked out of your device and cannot use it as intended until you agree. No way around it.
Youtube user AMurder0fCrows documented the experience in this video:
It seems like every time we take a step forward, like the passing of the cell phone unlocking bill earlier this year, we end up taking two steps back with abuses like this.
If you are interested in fighting abuses like Nintendo's outlined above, the EFF is working on related issues like DRM, the Right to Repair, and our Coders' Rights Project. Check out those pages for updates on those efforts.