As far as we know, the Officer didn't have a racist manifesto sitting on his hard drive that he uploaded to 8Chan 10 minutes before doing this.
So it's true
Other than the fact a white officer snuffed out the life of a totally helpless and indeed handcuffed black suspect using wildly incorrect protocol and in spite of the suspect's protestations that he couldn't breathe
Yep: other than that, no evidence of racism