I think most of the points have been addressed in #3427. I agree that black people are often treated unfairly by the cops, this includes being treated in a less lenient way etc. These are classic examples of racism, and people can always voice their dissent to these racist acts from time to time, but not making use of Floyd's death as it's a clear case of police brutality.
For the brutality part, however, I personally have some conservation. From the social experiment, the majority of participants including black people themselves were more likely to shoot at their black friend rather than a white stranger. While you may argue this is already a kind of racism, I think the definition would be too broad this way that basically everyone is a racist.
Many talk about police's bias towards the black, but they fail to acknowledge their own bias. They presumably think Chauvin murdered Floyd due to racial profiling, solely based on so-called history and pattern without any evidence. Using the same metaphor as before, it's like a murderer must also be a rapist just because many killers rape their victims in the society.
When a white man is knelt to death, it's police brutality; when a black man is killed in the same way, it's racism. It just doesn't make any sense. Those who see it this way are actually the greatest racists, because they view and categorize the same event differently. Now it seems people value black people higher than others, as their death arouses attention while few care about others.
Unlike others, I'm always prepared to change my mind, as soon as there is any direct evidence pointing to the involvement of racism in this particular case. Maybe someone would testify against him in the trial, maybe someome would leak some stories to the press. Honestly, I hope Chauvin can be proven a racist in the end, otherwise all these protests look far less legitimate and meaningful, as they have already been without a clear aim and a concrete demand.
Look up "shooting bias" this is a similar situation.
You don't need someone in a trial to testify that Chauvin had posted racist posts on FB or was a secret member of the KKK. That would make this an indiviual act of racism, this is not necessarily about individual acts (though it may well be) this is about institutional racism. The argument is Chauvin and many other police like him expected more problems and possibly violence from Floyd because of the colour of his skin and their preconceptions of what that meant.
What I mean is this. Police are more likely to shoot at a black person than a white person, this isn't necessarily because they hate black people. But they expect them to be more violent, they expect them to be more likely to have committed a crime - these are preconception and are just as racist as attacking a business because it is owned by black people.
What people arguing in this thread, that we don't know if this brutality was racially driven fail to get is that this institutional racism is endemic everywhere in the western world. Its the reason people are more likely in to hire a white person over a black person, more likely to want to rent their property to a white person rather than a black person, feel more comfortable with their daughter dating a white man than a black man etc etc. Their preconceptions make them fear.
A white person walking down the street late at night, are they more nervous of group of young black men hanging out on the corner or a group of young white men? The tendency to fear and expect bad outcomes from black people is everywhere and it is 100% racist and lots and lots people if they are honest with themselves will recognise this at one point or another in themselves.
The bigger questions are why? American history is obviously one thing, as there cannot be a white person on earth who doesn't understand that black America has been appallingly treated throughout the history of the US. But the media and popular culture has a lot to do with it as well, from everything from the Wire to New Jack City (2 random examples and certainly not saying that either are racist) paint a picture of black urban America as violent and gang ridden. Nerds, sensible people and goodies etc etc in movies and in books are rarely black and if the hero is black even then they often come packaged in a violent form, like Black Panther or Shaft (2 more random examples and not held up as racist films)
We are bombarded everyday by negative black stereotypes in US culture and sadly that is the dominant global culture now, this just builds those racist preconceptions in all sorts of people even those who would not for a second think they are racist.
On top of that segregation is rife in the US and has been for hundreds of years this in turn builds up an us and them culture which once again breeds institutional racism.
To argue that Chauvin's actions were not racist misses the point entirely, the black lives matter movement gets this, institutionally black lives are currently cheaper in the States than white lives.
This post has gone on much longer than I meant, but there are literally hundreds of books and papers written about this, I offer no answers or suggestions on how to fix this as I honestly don't know beyond individuals recognising it in themselves and working to overcome it.