The reason that black people in the US hate asians so much is that they disprove their narrative. Black people in the US continue to maintain that racism, white supremacy and slavery are the causes for their continued failure as a people. The fact is there has been a substantial reduction in racism and racist policies since the 70s in the US.
On the other hand, asians who have arrived to the US, most of whom with nothing to their name, have continued to far outstrip black people by every metric, and who also outstrip white people. The reasons for this are quite obvious and clear but difficult to stomach for black people. Asians typically have a very solid family formation and an incomparable work ethic.
When black people are forced to acknowledge the success of asians, they come up with all sorts of strange mental gymnastics, such as Asian people are white people's pet minority etc etc. The truth is asians have been treated terribly again and again in america, the confiscation of all property and internment of japanese Americans during WW2 comes to mind, not to mention the horror endured by Chinese Americans building the railways through the mountains.
The truth is, black people hate asians for their success, and refuse to acknowledge that their relative lack of success is due to their own doing, someone else must be at fault. This is most clear with Nigerian Americans of course, they are one of the most successful groups in america, are black, and are vehemently hated by African Americans.
In summary, there is very little asians can do about how African Americans feel about them, and moreover it's not their job. The overwhelming majority of attacks against asians are indeed from African Americans, but the reason you may think otherwise is due to the media's love of portraying white people as oppressors.
I'm reminded of the quote from John Wick, If you want peace, prepare for war. I think many Asians are beginning to realise this. In fact many of the asian martial arts are based on such a premise. As such the huge growth in firearm purchases by asians is heartening. People will think twice about attacking if you pull a gun in their face, smirk, and tell them to start praying.