There are plenty of lightweight operating systems out there. They're generally built for specific purposes, though. If you have more than one reason why you use a computer then you tend to need more OS features, where is typically where "bullshit" comes from. A headless Ubuntu or CentOS installation is fast and perfect for a web server or database server. You're not going to watch YouTube on it, though. The chances of getting an actually lightweight, no bullshit general purpose operating system are pretty low when you account for everything a general purpose operating system needs to be able to do.
That's why I'm happy that Valve has been investing in SteamOS and Proton they way they are. They're working to make an OS that's focused just on gaming. It's still going to have bloat in it because they are going to want to track you and advertise to you, and it's going to need to support drivers for tons of hardware configurations, but it's a step in the right direction.