Nvidia's biggest product is absolutely AI by a massive landslide, I'm pretty sure I read that the point of them downloading these videos and doing the training is to build a pipeline for their AI users to do the same with their own shit. (Can't be bothered to double-check cuz I really don't care)
So they aren't downloading all this video to make a crazy AI model. They're downloading all this video to make a tool for their AI customers to use, you may not agree but improving their product is exactly what they're doing.
¯\_(ツ)_/¯ great question