Because George Floyd was killed by the police, who are held to a higher standard in society. Had George Floyd been killed by 4 random non-police officers, it probably wouldn't have made the Minneapolis news.
I just don't know why that concept is so hard for you to grasp.
I'll go further and add that it's complete lack of accountability on the police departments' part. The killer in this case was arrested and will face justice--how often can we say that about cops who kill, rather than "protect and serve" as they're supposed to? If they routinely faced the consequences the same as any killer I doubt the present level of outrage would exist.
Most police killings have enough deniability where it would be highly unlikely to get a conviction and still have officers willing to do their job. The Atlanta shooting is a good example - there is no way that case holds up to a "beyond a reasonable doubt" standard. Chauvin is a very rare exception.
