“Microsoft’s stated intention was that Windows Update would only apply the SBAT update to systems that were Windows-only, and any dual-boot setups would instead be left vulnerable to attack until the installed distro updated its grub and shipped an SBAT update itself.”
Microsoft pushed a Windows update that told machines to stop trusting old, vulnerable versions of grub. It was supposed to skip dual-boot systems. It didn’t, and Linux installs died at a “Something has gone seriously wrong” screen. The distros that never bumped their grub security generation share the blame. The people who paid were end users who just wanted their computer to boot.