Atlanta Area Cops

I just need a wee bit of clarification: A cop at the Atlanta Airport is fired for throwing a woman to the ground. Meanwhile, Gwinnett county cops (in the Metro Atlanta area) are not so much as reprimanded for killing a handcuffed and shackled man with a taser. So we fire a black cop for what at most can be considered manhandling (definitely not brutality in the scheme of brutality witnessed from some officers) a white woman. And we do nothing when eleven officers kill a black man (a restrained black man) with the excuse that they were attempting to restrain....how much restraint is needed for a handcuffed and ankle shackled man????