It's not just about race. I am an average white guy, and I'd still find it hard not to talk to the police. The police has guns, and more importantly, has the state behind them. So I'm intimidated by default (and it's partially how it's supposed to be - the police is supposed to commend respect). Refusing to answer a politely asked question feels like an escalation (and will likely be received as such). I'm a law-abiding citizen, we should be "in it together", me answering their questions should help us both in ensuring bad people get caught and good people stay safe. It's a very unhealthy situation if cooperating with police by default is seen as dangerous.