Leonard Pitts: We don’t have a few bad apples. We have a rotten tree.

After George Floyd became the latest unarmed African American killed by police.After cars were overturned and cities were burned.After armies of angry people filled our streets with raw screams.After all that, a white man with an impressive title went on CNN to explain things. "I don't think there is systemic racism," opined National Security Adviser Robert C. O'Brien. "I think 99.9 percent of our law-enforcement officers are great Americans."So why do these great Americans seem to have such tro