That's fine, I'm not saying you should like it, I just want to explain it. The clips are from inside the game, and I thought they figured out aliens were not humanoid during the first book, but that was just in passing.
The Dark Forest book talks about how every civilization in the universe is trying to hide from each other, and when Earth sent that signal in the first book, everybody noticed Earth exists, and it was just a matter of time until some more powerful civilization would try to take advantage.