The popular narrative is that these crimes are due to Americans still thinking that Asian people caused the pandemic. It's even become a bit of international propaganda against the US. There's likely some truth to it. But also, the US has a broken mental health system, and our cities are overrun with people who may not be capable of understanding the consequences of their actions, so it's hard to prove or disprove. I will say that Trump calling it the "China flu" probably helped radicalize those who are incapable of knowing better.