Essentially The Rule of three and the Wiccan Rede can be summed up in two phrases. What ever you put out in the world comes back to you three fold, and "An it harm none, do what ye will". Both of these are essentially meant to be advice for leading a responsible and respectful life, and work off of the basic principals of Karma. Many people I've talked to in the past however don't seem to take these phrases as advice meant for interpretation rather as strict guidelines meant to be followed to the letter, and are even inescapable. They believe if they do the smallest disservice to any living creature they have to sit and wait for the karmic three-fold fury that is bound to come their way.
Now if you see these as rules which are essential to your emotional and mental well being. By all means I have no gripe with you and you should feel free to live life as you choose. I personally see no real world proof that these are clear tenants of the universe. Also I believe that at times we live in a cruel and unjust society wherein only the strongest survive and occasionally yes that does mean that someone may get hurt and it might be at your doing. Do I think you should seek these situations out, of course not. I'm just not afraid to fight fire with fire, and if someone is damaged in any way (mentally, emotionally, physically) by my hand I accept responsibility for my actions. I certainly don't feel good about it, but life is full of mistakes and I can't spend my entire life walking on proverbial eggshells. Not really sure if this made any sort of clear sense but those are just my thoughts on the subject.