Beagle, its the old "The ends justify the means" argument dressed up in new clothes.
However this deeply flawed theory was comprehensively demolished by about 1850.
The simple reason is that human beings are not "means" to an end, they are an end in themselves. Here endeth the philosphy lesson.
The tragedy is that the few who do abuse and torture are besmirching themselves with the same foul slime that our enemy is covered with.
To put it in very simple terms for people who can only count to 16, two wrongs don't make a right.
Some of you might like to find a copy of the "Manual of Field Security" and read it.