I’m not able to read the cited reference at that link, so I’ll try to take the statement at face value.
I could name or describe a number of systems right now that have outcomes that we could all agree are contrary or misaligned with their purpose, so unless the author is equivocating things like “purpose”, or “system”, I don’t think your premise is well founded, nor do I think your conclusion has merit.
The conclusion is that systems should not be judged deontologically, and instead should be judged consequentially.
The point is that if you could describe systems that are contrary to their purpose and have negative outcomes, one is justified in referring to them as systems whose purpose is that negative outcome. Doing otherwise is arguing from conclusions.
It's naive not to. Believing that Facebook's purpose is what it intends to do is like believing that North Korea is a democratic people's republic.
I can rephrase it in terms of intentionality if you wish:
Meta has a choice every day to exist or not and the not. When choice to exist results in the sexual harassment of children then transitively Meta is choosing that consequence.
To address your knife analogy, a knife alone is not a system. A knife plus a human plus another human being stabbed by the knife is. In that scenario, the person creating the system, the knife-wielder, should(like Meta), choose to dissolve the system. I think, at least for the knife+human+human stabbing system, that's quite easy to agree with.
In this case, one of the purposes - there are others - of Meta is the sexual harassment of children.
Meta could self-dissolve, or cease operations, but rather than that, they continue their purpose. Implicitly, the sexual of harassment is worth it.
1. Beer, S. (2002). What is cybernetics? Kybernetes, 31(2), 209–219. doi:10.1108/03684920210417283 https://sci-hub.ru/10.1108/03684920210417283