Yes. I wonder why they chose the wording they did. It seems like it would be more useful to know if people think their jobs actually are bullshit. Even if office assistants feel like crap about their job I imagine a lot of them would be missed. Likewise, I imagine there's plenty of teachers that would criticise the way they're being utilised.

For referance:

He analyzed survey data on 1,811 respondents in the U.S. working in 21 types of jobs, who were asked if their work gave them "a feeling of making a positive impact on community and society" and "the feeling of doing useful work."

Edit: Ah!

To test the hypotheses derived from Graeber’s theory, binary logistic regression models are estimated with perceived job-uselessness as the dependent variable, using data from the 2015 American Working Conditions Survey (AWCS) (Maestas et al., 2017). The AWCS is based on the RAND American Life Panel, which is a nationally representative sample of individuals living in the US who agreed to participate in regular online surveys.2 From this panel, a probability-based sample was drawn for the AWCS and 3131 responses were registered in total, which accounts to a response rate of 64%. This dataset was chosen mainly for two reasons: on the one hand, it includes a wide range of work-related variables. To the author’s knowledge, it is in fact the only dataset available that allows to control for all factors mentioned above, which is a crucial part of the analyses in this article. On the other hand, it provides data from the US, which is especially interesting since Graeber’s theory may only apply to heavily financialized Anglo-Saxon countries and the US has not yet been analysed individually to date.

Data collected for another purpose was being used. That's why.