I think it is mostly the polarization of political discussion. If one side stretches the truth to say that the McMichaels were in fear for their lives, the other side will stretch the truth to say Arbery was only jogging. When "only jogging" is introduced, the first side starts stretching even further, then the second side stretches further. Before long, the truth of what happened isn't important to the people who are arguing, only winning the argument against the other side.
I don't care about "showing those rednecks", and I don't care about proving to a local "rabble rouser" that he wasn't just jogging. Was he up to no good? I don't know. His actions in the video look a little shady, but I don't see anything that would convict him. Even if he was intending to commit burglary, does that justify assault with a deadly weapon? No. If it permissible to defend yourself if assaulted with a deadly weapon? Yes. Can a person who commits assault with a deadly weapon use the victim's response as a reason to kill them? No.
I try not to play in to the spin and fluff that accompanies news stories and side-vs-side arguments about those stories. Even if one "side" or the other in an argument overstates information, it doesn't mean that their are completely wrong about everything.