It is not arbitrary. 

Were I able to enter it as a 1099MISC as in previous years I would have marked it as other income. 

The idiots mailed him a 1099NEC which I believe is just a mistake.

From what he's told me it's just residual income, not income he worked for. He's a wage employee with no schedule C. The 1099 is $147 and creating a schedule C for this income would be preposterous, at least in my opinion. Furthermore, if I did so, I would have to come with expenses that do not exist, which would actually be arbitrary. 

He's not the only one of my clients who receives one of these for income that was not actually self-employment income. Were the income more substantial I would ask him to get a corrected 1099, as it's only $147 I am not going to bother.