@renatoram There are some calm voices on YouTube, but the algorithm makes it hard to find. I like Mark Brown's video series "Game Maker's Toolkit", which isn't really shouty at all. He just talks, calmly, about how cool bits of how games work and don't work.
Most other videogame YouTubers are indeed, all about exaggerating their reactions to the point of absurdity, which means that they spend a lot of time yelling. It's an attempt to garner more views, I think.