They don’t like it because it’s mostly implemented in microsofts favor. It’s shipped with microsoft keys by default and needs to be disabled to boot a lot of linux distros. If there was a more unbiased way to load a new os like a default key setup routine at first boot or a preinstalled key for major linux distros they wouldn’t be so hostile towards secure boot. The technology isn’t bad and it’s the only way to not have somebody temper with your system at rest without TPM.
What i love about musk is that he is the best bad example. Maybe someday he’ll start a war with some country and then people will start to understand that no single person or group should hold this much power. Because there are also a handful of other people and groups with the same resources who choose to hide in the background.