I think that’s a valid point for something like tetris, but the law isn’t specific in that sense.

Ok...how am I wrong? If the stream shows what happens in the game including story elements AND how the game is played/progressions then how am I wrong?

Wrong. Your still spoiling the story, gameplay, cutscenes, and the experiences offered by the game you could only get if you played it. Not different from a movie or song.

I think this was a way to bring it to YouTube and the public’s attention more than anything else.

A let’s play streaming a game is different from critiquing or a parody. It really isn’t different from putting a movie or TV show up without permission.

Well technically the stream is on YouTube, so it’s their property. So if they want to honor a DMCA request without seeking legal interjection, they can.