"So what the Rede is saying is that those actions which do not cause harm you are free to do as you see fit. The Rede is absolutely silent on actions that do cause harm, leaving those up to the situation and the ethics of the individual Wiccan to determine which actions are right and justified."
I think because we're so used to religions full of laws and rules and punishments, the fact that the Rede is a proclamation of your freedom, not a moral restriction, just sails right over the heads of a lot of new practitioners (totally sailed over mine!).
I know we're specifically talking about Wicca, but I'd like to take a quick field trip to its cousin, Thelema. In Liber AL (our main holy book) we're told that "Do what thou wilt shall be the whole of the law," and that "love is the law, love under will," and Crowley briefly explains how to live with Love as the law without becoming spineless;
"This is to be taken as meaning that while Will is the Law, the nature of that Will is Love. But this Love is as it were a by-product of that Will; it does not contradict or supersede that Will; and if apparent contradiction should arise in any crisis, it is the Will that will guide us aright. Lo, while in The Book of the Law is much of Love, there is no word of Sentimentality."
What Crowley is essentially saying here is that even in a world where the very law that governs it is love, that is not a call for you to sit on your hands and do nothing while your family is harassed or harmed or whatever else. If you truly believe in pacifism, more power to you (pacifists are way braver than anyone gives them credit), but you in either case have every right to defend yourself and those around you. After all, letting their disruptive act of hate go unstopped and unchallenged isn't particularly loving either, now is it?
The choice to use magick for something like a curse is very personal and totally up to you, but remember that Wiccans can and do join the armed forces of the world, and even in perfect love and perfect trust they kill the enemies of peace and freedom.