Earlier quoted context omitted.
Why? How does this affect them on macOS at all? If Bash were also being used on iOS that would be different, but I'm quite confident that will never happen.
Again, perhaps it is because Apple is planning for a future where SIP and Gatekeeper cannot be turned off. A future where macOS is basically reduced/merged to iPadOS. Time will tell.
But preventing ALL Macs from turning off Gatekeeper and SIP? I think that would be unpopular.