What I know is that there is a tremendous groundswell of anguish among POC and especially black people about the upsurge in racist acts and especially killings that are not brought to any kind of justice. While I do not know this poet's mind, of course, my first take was that this, in general is what is referred to.
As for sensitizing oneself to all this, I recommend highly reading current (and actually also not so current) black writers for a feel of the state of things. Have just read through, for instance, Jericho Brown's The Tradition (poetry book just published) I have some kind of awareness. The constant microaggressions of a racist culture build a kind of platform on which the acts of tragedy and senseless death play out, and there is a great build-up of anguish because of it.
I was just that moment, before checking in here, reading someone's tweet that said, if you are going to write about a marginalized people, do it with respect because it is like you are walking into our house, into our bodies. I think that is a great key, but of the "necessary and not sufficient" kind.
It's good that you know you have that blind spot. Racism is in part founded on invisibility. "They" don't really exist because we have all been segregated into our assigned areas. It's a deadly poison.