I don’t speak for all Linux users, but it’s not like we don’t like the tech or the concept… We don’t like it because a lot of the time it’s just another way for Microsoft to throw around their weight, you need a valid key to sign your kernel images with to be able to boot another OS instead of Windows, and some motherboards don’t support installing your own keys as trusted keys. But usually there are ways around that issue nowadays.
And also it’s not an easy process if you’re not an advanced user of sorts. You have to know what is entailed, what to use, where to store your keys safely, have a script to re-sign the kernel image every kernel update(which happens every week on something like Arch), etc.