All you need to do is to know about the linked page and have it open on another computer, disable some initial disk protections, reboot into recovery while holding down some unmentioned key combinations, disable further restrictions by typing in cryptic Terminal commands that don't match the public names of the features they affect, reboot again, type in more cryptic commands as root to modify deeply nested system files and perform filesystem voodoo, and then reboot yet again with an optional prayer. Repeat for every OS update.

What could be easier?

When OS X was introduced, asking on Apple forums how to run as root was almost a daily question.

Most consumers don't care about security, making it easy to disable just opens the floodgates of their systems.

And will you even be able to do it tomorrow?

Fighting the OS you are running is an uphill battle that gets tiresome real quick.

First boot: “Do you wish Apple to receive ... for your security?”

Most users will say yes.

Technical ones at least can say no.

Easier than setting up bluetoooth.

The easier it is to opt out, the more likely it is for sketchy developers to guide tech-novice users through that process, the more likely it is for malicious actors to take advantage of those who opted out.