Why is Nintendo targeting this YouTuber?

Because OP is lazy.

Retro Game Corps published a 14-minute video about how well Nintendo Wii U games can run on Android handhelds.

Big daddy N then DCMA the video to oblivion and this wasn't the first time big N did this to him.

I deeply dislike Nintendo.

This is why I'll never buy anything Nintendo again. They've made too much of a habit of fucking over people.