Because the alternative is doing nothing. If your every decision at your job is qualified by the possibility that someone else will come along someday and exploit your actions to the worst possible end, you would never get anything done.
I'm building software. But who says the algorithms I develop cannot be used maliciously, just because I won't do so myself?
The alternative is to do the right, thing as difficult a call as that may be. It doesn't mean you throw the constitution through the shredder or sit with your head buried in the sand. It means you make the calls that don't involve trampling over fundamental rights of human beings (citizens and non-citizens alike) in order to save them.
If you can't make these decisions without doing either, then you don't belong in that position. As idealistic as that may be, society is far more organic than mere algorithms and functions; thus capable of being reformulated as necessary.
I recognize that you believe this alternative exists. I don't. I believe every action that could be taken is wrong, including no action. I believe that one of the core properties of any system is exploitability, including legal systems.
> As idealistic as that may be, society is far more organic than mere algorithms and functions; thus capable of being reformulated as necessary.
...how many instances of "reformulation" can you name of society, as compared to systems of algorithms and functions? Changing society in a meaningful and directed manner is damn near impossible. Algorithms get reformulated hourly.
I'm building software. But who says the algorithms I develop cannot be used maliciously, just because I won't do so myself?