That is one possible interpretation, but it is certainly arguable against.
Or maybe it is evil to NOT torture under such circumstances... by labeling the torture of child rapists wrong and evil and forbidden you are directly causing more children to be raped. Which is an evil act.
This is NOT justifying "torture the evil act", that is saying that NOT torturing is an evil act.
And what the hell is wrong with JUSTIFYING actions? You better have a pretty damn good justifications for moral choices you make otherwise you are just randomly doing things without sense or reason. Justifying things means "making them just", and its a pretty good term because it can do exactly that when done CORRECTLY.