Honestly, I think everyone is a bit racist. When people don't look or behave like you, it's easy to treat them differently, sometimes a lot differently.

I work with people from a variety of backgrounds (race, language, nationality) and I'm married to someone with a different race, language, and nationality as well. Even so, when I read articles online, I picture the other person as my race, background, and gender, even though that's unlikely to be the case. I also catch myself thinking less of someone who is different from me, before I catch myself and really think about what they said/did (usually it's just the accent or mannerisms throwing me off).

I think that's normal, and you're doing the right thing by acknowledging it and trying to catch yourself. The next step that works for me is to build trust with my co-workers who are different from me, and ask them if I'm being insensitive or something. It takes time to build that trust, but my spouse calls me out all the time and I express my gratitude each time. I still make mistakes, but hopefully those around me know I don't mean anything by it. I also catch my spouse being racist, and they're a bit more defensive about it but appreciative nonetheless.

Good luck! Life is all about continually improving ourselves. I don't think we'll ever reach a point where racism is dead, but hopefully we can get to a point where it's at least manageable.