mistakes are one thing but intentionally flagrant actions is the bigger problem
Chauvin kneeling on Floyd's neck wasn't a mistake; it was a intentional act. I don't think Chauvin thought he was going to kill Floyd but the point is mute; he made a conscious decision that was unreasonable and led to Floyd's death
Mistakes are a lot more complicated. The cop that killed the drunk dude in the Wendy's parking lot...I'd classify that as a mistake. A lot of it was in the moment, high adrenaline, fight or flight stuff and he shot his gun when the situation didn't exactly call for it. I don't think the cop should be left off the hook but that situation is a lot more understandable in my opinion.
The Chauvin thing was so categorically different that it probably is important to nail down the necessary elements of reform. Chauvin might be a homicidal sociopath considering that disgusting indifference to human life, that thing in GA was a matter of policing tactics, and reasonable people could disagree about. In these situations, there are definitely factors that make the officer's actions defendable. For me, this gets wrapped up into the warrior cop persona that some of these cops adopt and that is fundamental to the reforms that are necessary to improve policing across the country.
Which to me arrives at the point that should be argued. If you are someone that see's that shooting in GA and says "I'm content with how that situation unfolded" than I think you are a psycho and irredeemable. If you are someone that looks at it, agrees that it is unfortunate, but does not view the circumstance as punishable, or not an indications of questionable policing approach, I think we can at least have a discussion about why we think what we do.