Being a white guy who has worked as a clerk and who has periodically been mistaken for one, my white male privilege lets me know the people who asked me if I worked there were simply looking for help and I was the nearest person dressed in a way that suggested I might be able to provide it.
But for insecure privileged people, being mistaken for a mere worker is a great insult.
There's a related manifestation of classism: privileged antiracists will use a working class dialect associated with their race to mock white people by pretending the white person expects them to talk like that. Bourgie black folks use ebonics; affluent Asians use pidgin. Here's Arthur Chu on Twitter:
I noted the other day that this is funny because Sunkara is not a white man. But it's also funny because of who Chu is. Wikipedia says his parents came from Taiwan, where many of China's rich fled at the end of the Communist Revolution. Being Taiwanese suggests his parents came to the US with some wealth because they couldn't have been refugees, which may be why Chu graduated from one of the schools for America's privileged, but whatever the reason for Chu's privilege, when he affects pidgin, this matters:
1. He did not grow up speaking pidgin.
2. He is not descended from Asian American workers who spoke pidgin.
Chu appropriates pidgin to mock Sunkara, the "white man" he believes he is addressing in that tweet, by mocking the speech of working-class Asians. He asserts his superiority to the "white man" by taking on a cartoonish version of the language of people he sees as inferior, the poor workers who learned an English dialect by ear because they could not afford schools that taught the rules of middle and upper class English. His intended humor comes from the fact that he does not actually speak pidgin—he is asserting his superiority by suggesting the "white man" he is addressing is foolishly expecting him to speak like an inferior.
Now, you may say I'm reading too much into Chu's use of pidgin, but note the context: Sunkara is saying class should be the primary concern of people who care about racism and sexism because women and people of color are disproportionately harmed by the US class system; Chu is rejecting that.
Ah, well. Chu is hardly the only privileged person concerned with the ways racism and sexism affect his privileged peers who feels no need to put class high in his priorities. For privileged antiracists and antisexists, equality is about the opportunity for rich women and people of color to exploit workers of all hues and genders with the same freedom that rich white men have always had.