JB, I am very sorry to hear about your situation and I can definitely relate to it (I had to shoot a neighbor's Pit Bull that was overly aggressive). It really sucks how they are making you look like the one at fault considering the breed (if i read Rottweiler correctly) has a history of being aggressive at times. Mostly just part of being a good guard dog, but it can lead to instances like this.
All you need to know, and I'm sure you do, is that you did what you had to do to protect your son and yourself. And anyone bad talking you obviously would put an aggressive dog's life before their own family and, IMO they might as well use the muzzle that these dogs should have had.
Sorry if that seems a little harsh, but when people attack someone else's actions, especially in this instance, I get a little defensive about what our society is coming to...
Again, as far as I'm concerned, you handled this as good as anyone. And considering you only had one shot, I am very impressed.