Hold up a second. The question that was asked was who benefits. It wasn't who's behind it. There's a difference. The fact that China benefits is really hard to dispute, and is independent of their actions or involvement. I don't think there's any serious doubt that China benefits. Almost anything that hurts us helps them.
It's a separate question, one which was not asked and I did not previously address, whether or not they are involved. But the fact that they have motive should certainly give one pause to consider the possibility. As to the apparatus, there are lots of channels available to do so (for example, facebook groups and ads, etc). They need not have murdered anyone in order to help amplify and radicalize the response to those events. And in fact, the CCP's public response to the death of George Floyd is a textbook example of communist propaganda efforts to paint the US as irredeemably racist (which is ironic given their own racism). Now, even if China is surreptitiously encouraging unrest, that wouldn't mean that there would be none absent China. But given that they have the motive, and the means to encourage unrest are within reach of any state actor, it would be foolish to simply dismiss the possibility.
I will also note that China is a primary source of fentanyl, which is causing serious drug abuse problems here in the US and was involved in the death of George Floyd. So no, actually, China doesn't have their hands clean in his death.