And what if that customer wants to run their own firmware, ie after the manufacturer goes out of business? "Security" in this case conveniently prevente that.
Tradeoffs. Which is more likely here?
1. A customer wants to run their own firmware, or
2. Someone malicious close to the customer, an angry ex, tampers with their device, and uses the lack of Secure Boot to modify the OS to hide all trace of a tracker's existence, or
3. A malicious piece of firmware uses the lack of Secure Boot to modify the boot partition to ensure the malware loads before the OS, thereby permanently disabling all ability for the system to repair itself from within itself
Apple uses #2 and #3 in their own arguments. If your Mac gets hacked, that's bad. If your iPhone gets hacked, that's your life, and your precise location, at all times.
Then that customer shouldn't buy a device that doesn't allow for their use case. Exercise some personal agency. Sheesh.
you click the box to turn off secure boot