I don't think he's saying 'it cannot be physically made to work (given enough effort and discipline)'. The impression I got was more like 'if you go down this route then the incremental path of least resistance leads somewhere bad'.
The range where databases work fine is pretty small. Sudden spikes in job creation will kill the performance of the database. Often enough the job creations come from external systems you can't control.
Databases actually work fine as a queue but emotionally you don’t like it. That’s fine it’s just not real strong objections.
What you have not said is “it physically does not work”, and that’s because it does work fine.