You honestly believe Let's Plays don't show the vast majority of the games? You honestly want me to link you to the countless Let's Plays that are there?
Nintendo isn't saying you're not allowed to post videos. They're saying that if you intend to monetise the videos to gain profit, then they, rightly, want a small portion of said profits since it is their material people are profiting from.
You're allowed to make videos with Nintendo content. They're not stopping this.