This is basically propaganda for the war on general purpose computing. My user data is less safe on a Windows device, because Microsoft has full access to that device and they are extremely untrustworthy. On my Linux device, I choose the software to install.
What are you talking about? This has nothing to do with general purpose computing and everything to do with allowing you to authenticate the parts of the Linux boot process that must by necessity be left unencrypted in order to actually boot your computer. This is putting SecureBoot and the TPM to work for your benefit.
It's not propaganda in any sense, it's recognizing that Linux is behind the state of the art compared to Windows/macOS when it comes to preventing tampering with your OS install. It's not saying you should use Windows, it's saying we should improve the Linux boot process to be a tight security-wise as the Windows boot process along with a long explanation of how we get there.