You're either racist or anti-racist. There's no such thing as merely "not racist," thought I think there is a difference between active and passive racism. Passive racists often say they're "not racist" because they're not actively trying to be racist (i.e. they aren't KKK members or they don't tell jokes about minorities). But if you're not being actively anti-racist, you're passively contributing to the perpetuation of systemic injustices (likely because your life isn't directly affected in a way that you notice). If you're not fighting racism, that means you're helping it.