I think you mean you are being a prescriptivist. In a descriptivist action, they added the new definition to Merriam Webster like 2 years ago. This is because they decided it makes sense to have a different and more useful definition of "racism" and "racial prejudice."

the purpose of refining the racism definition as "power + prejudice" was to move discourse away from the idea of being racist as a personal failing, and instead focus on structural oppression and the material reality of minority groups.

Basically liberal society largely seems to have conceived racism as 'being irrationally mean', but for people with a materialist anti-racist perspective, that definition isn't productive or insightful and the lack of material, tangible progress for black people post-civil rights made it clear that there needed to be more focus on power dynamics and historical context to combat racism.

I'd recomend Beverly Tatum's work , her perspective is very informed and compelling