It's hard to tell without knowing the man directly, so answering the question actually shows as much about our assumptions about how to define and imagine racism as anything else.
My read of the man is this: He is a narcissist. He is only concerned about attention. Positive or negative, it doesn't matter. He will take hatred and scorn.
He probably does have a lot of subconscious biases. These are aided by the privileged life that he lives that makes it very easy to never have to question his interactions with others. I think a lot of his anger is something he might honestly feel at that moment.
But anyone who knows a narcissist knows that they don't really believe anything. They may think they have convictions the same way that someone who refuses to check their bank account thinks it's probably okay: Some part of them, deep down, knows that they don't.
The interview he had with Stephen Colbert shows a lot of this reality. When Colbert just treated him with respect and didn't give him the chance to turn up his circus, everything seemed half-hearted. He was saying the same things but he was saying them to an attentive, nodding face. He was having to face the emptiness he feels inside.
The problem is that Trump's behavior speaks to people who have much more actual hate. He's letting anyone with a grudge find a new way of yelling about it.