So basically there's a distinction between experiencing discrimination/prejudice due to your skin colour in a one-off experience, and experiencing it as part of a structural system of discrimination.
Traditionally, and as per the dictionary, we call the former racism and the latter structural or systemic racism. What people would prefer is to call the former prejudice based on skin colour, and the latter racism.
In the end it amounts to the same thing. It's just semantics. Why try to change established definitions? Just creates pointless arguments like we see on this thread.