I think that the A's are venting their frustration and anger. It is hard enough to lose Caylee but there can be no putting this behind them given that KC killed Caylee and that whole situ is so stressful week after week and will go on for months/years before resolved at trial.
The A's are going stir crazy and are venting against any target they can, they cannot vent against KC, if they would since KC is in protective custody so the memorial and those who keep it going become targets. The A's are aggressors, they will never begin to heal and move on until they can ignore these actions, not seek them out to vent against and, can accept that KC killed Caylee and she isn't coming home anytime soon.
It is hard for the A's to move on, just like Groundhog day, they relive it every day. Same repeat. They are angry aggressive A's. Angry at the world. Sad for them, pitiful. They need to rise above vigilante tactics.