[noam_compsci]

This isn’t correct. The author calls bullshit jobs anything in the service sector.

The book takes the approach of “these people say their job is bullshit” to be tactful, as dunking on people is seen as a generally bad thing to do.

[marcod]

I believe you read that wrong. He said that service jobs provide something essential to customers, even if they aren't well paid and can often be quite soul-sucking and are explicitly not the BS jobs he's talking about.