If the desired outcome is world peace and the means of which is murdering every human then I don't think the desired outcome is all that relevant.

Is this HAL from space odyssey?

Let's include who is pushing for the new policy right up to the head of considerations, because these "child protections" are not child protections, they are using children as fear vehicles to make political careers and to generate new revenues for their tech security company backers. Calls to "protect the children" rarely are about children at all, but are almost universally a vehicle to usher in some Orwellian fear-laced perspective forced on the public.

Why would the desired outcome be a more true test than the actual outcome?

The test is whether or not the desired outcome is being achieved.

Yes, but my point is what weight would the desired outcome have? Why not just observe the actual outcome and judge it directly?

You're saying the true test of a policy is its stated intentions? This attitude is exactly why we get so many terrible, unworkable policies with terrible unintended consequences (though often the consequences are so obvious that the claims that they are "unintended" are incredible).

The test is whether or not the desired outcome is being achieved.