Your definition of racism is too expansive. Few people are racist under the actual definition of racism, which is believing that members of a certain race are inherently inferior to one or more races because of their race. I don't think that belief is a default belief. And it's easily falsifiable as soon as you encounter counter evidence.

Here's what "everyone" does. Everyone has confirmation bias and availability bias. Everyone uses statistical information to predict human behavior. We pick up on trends. And so if you see a black person, for example, doing something strange in public, or latino girl who is pregnant at a very young age, or a an Indian person that smells a bit spicy, we store that information. And then when we see (or smell) it a few more times, and learn about stereotypes. And then when we see it again we kind of aren't surprised. Because we've built a statistical model of the world that is more accurate than arbitrary. That same model might include a tendency to be more comfortable around people who look like you. Because you're parents fed and supported you for years. You might have grown up hanging around people like you.

That's not racist. It might lead to prejudice. But if you end up drawing unfair conclusions or discriminating against people based on race, that is racist. But I don't think everyone does that.