Assuming it suggests bias in favor of black suspects is assuming a hell of a lot about the accuracy of the simulation relative to real life and whether or not it captures bias or peoples beliefs about how they are expected to act or changes to e.g. fear levels, that are not supported (it's also not contradicted - there's as far as I can tell no data either way) by the experiment in question.

All it tells us in isolation is that this is how a set of people in current society acts in a simulation of that kind. It does not tell us why, and trying to draw conclusions about why without further experiments is irresponsible.