There are people out there that are crazy, and will use anything to justify their actions. Unless he called for a specific action, I don't see how he is to blame. It would be setting a bad precedent to blame or punish anyone that said something provacative that is not explicitly a call for inciting harm/violence. People need to be held responsible for their own actions.

I believe Obama used carefully picked statistics to say there is widespread racism in the police. There are likely racist people/cops, but I don't believe there is evidence to suggest widespread racism.