"show business" is not necessarily derogatory in USA's use. "That's show business" is definitely often used to say "it sucks but that's how things are", but "show business" as a whole is also used to say "this is how the top tier does things, pay attention".

Maybe another way to describe it is: Hollywood ("show business" as a whole, but it leaks into popular media in many ways, thus popular [anything]) has a huge presence in both positive and negative ways.

As usual in idioms, context is extremely important / often more important than the words themselves. "Show business" is a reference to a highly visible and influential segment of [a population], though often devoid of analysis beyond that point.

It’s an american idiom. Just means they are hard working folks.