>No. Because you cannot outweigh a wrong by another wrong. There's no balance, it only adds up on wrong.
This is not in line with consequentialist thinking, so there is no logical fallacy. You're failing to consider a line of reasoning in terms of a different moral philosophy to your own.
>They are also to all the rest of society that, witnessing that, can only deduce and fear that _no one_ is safe from being wronged the same way, because of the actions of a third party (be it family or other).
As other commenters have pointed out, this is not a statement that holds in general in consequentialist terms. How great are the harms to the rest of society? How great are the harms of the crimes prevented in this way? What is the real net benefit or downside to the whole population? These are the questions consequentialism wants answered to judge the morality of such a policy.
> This is not in line with consequentialist thinking, so there is no logical fallacy.
Ok, but then what's the point of a consequentialist take, if that's so removed from past experiences?
> These are the questions consequentialism wants answered to judge the morality of such a policy.
Correct. The problem/flaw is deep in the roots of consequentialism itself: if you wait only for the outcomes to judge whether something is moral or not, you can only be a spectator, not an actor. You can't act without a principle. If you want to take action, you've got to act after principles, from memory and/or reasoning (or you may act irrationally - but then you may only invoke amorality, which defeats the consequentialist definition as well).
This is not in line with consequentialist thinking, so there is no logical fallacy. You're failing to consider a line of reasoning in terms of a different moral philosophy to your own.
>They are also to all the rest of society that, witnessing that, can only deduce and fear that _no one_ is safe from being wronged the same way, because of the actions of a third party (be it family or other).
As other commenters have pointed out, this is not a statement that holds in general in consequentialist terms. How great are the harms to the rest of society? How great are the harms of the crimes prevented in this way? What is the real net benefit or downside to the whole population? These are the questions consequentialism wants answered to judge the morality of such a policy.