Not on point for a bunch of different reasons, imo. But, ultimately, asserting a defense that "the victim was known to be violent" to justify attacking him with a baseball bat is completely different from asserting a defense that AA "attempted to take McMichael's gun" and therefore their actions were reasonable under the circumstances -- which is what the defendants in this case are saying.
From the link:
At trial, the State stipulated to Carter's introduction into evidence of a police report that charged the murder victim, Edwards, with aggravated assault. The police report stated that Edwards and another man had once chased an individual whom they believed had burglarized the other man's home, and assaulted the individual with a baseball bat. Carter intended the evidence to support his justification defense by showing Edward's purported propensity for violence. In response, the State contended that Edwards had not assaulted anyone, but rather had merely effectuated a citizen's arrest. At the State's request, the trial court gave a jury charge on citizen's arrest.
Even though slight evidence is enough to justify the giving of a jury charge,[12] we conclude there was not sufficient evidentiary support in this case to warrant the trial court's charge on citizen's arrest. Although a private person may make a citizen's arrest under OCGA § 17-4-60, only force that is reasonable under the circumstances may be used to restrain the individual arrested.[13] Certainly under the facts that were recounted in the police report, Edward's alleged assault of the individual with a baseball bat entailed the use of unreasonable force, and could not have been part of a legitimate citizen's arrest. Accordingly, the trial court erred by charging the jury on citizen's arrest. However, in light of the overwhelming evidence of Carter's guilt, there is no reasonable likelihood that the erroneous charge lessened the State's burden to prove all essential elements of the crimes charged beyond a reasonable doubt, and therefore the error was harmless.[14]