Remember the definition I provided:

Prejudice + Power

Power as in "Systemic power". The Irish, Bosnians, German Jews in ww2; these people all had systems of oppression using their power to oppress them in their countries. It's not as simple as "LawlSkinColour".

In a majority of situations, the word racism does not apply if you are the dominant socioeconomic ethnic group in the world, which white people are. You have to take context into account though, because life does not exist as a binary. In North America, Jewish and Irish folks can experience Racism. In spite of being largely white presenting, they are ethnicities that have been historically discriminated against.

White people as a blanket "race" though, cannot. Saying "Bill pisses me off because he's Jewish." is racist. Saying "Bill pisses me off because he's white." is an entirely different conversation. Jewish folks are one of the most historically discriminated against groups in the world. White folks have been the most dominant socioeconomic racial group in the world perpetuating oppression. To treat those two groups as if they are the same can only be done if you ignore all historical contexts. That is a wildly intellectually dishonest way to define the world.

Black, brown, Asian, and indigenous folks can, have, and continue to experience racism. The socioeconomic racial group that we call "white people" cannot experience Racism. The individual ethnic groups within said racial group can experience Racism.