The game isn’t “promoting” the idea of killing BLM protesters, and even if it was, that still wouldn’t be racist. BLM and the idea that black lives matter are not synonymous. In my opinion all this game does is debase the idea that BLM protesters are to be taken seriously. One can agree with the proposal that black lives matter without treating BLM as anything other than an embarrassment to progressive attitudes, and fair game for goofy satire.
As an aside, I don’t think we need to heal the relationship between cops and minorities. Cops are the whole problem, not just a problem for black people but for everyone. All BLM does is muddy the waters and sow racial division where none need exist.