While every CAM system is different, your assumption is correct, needing to model threads is absurd. First off, threads can be generated using taps, thread mills, single point cutting on a lathe or rolling.
IMO, non of those operations require modeled threads.
Some CAM systems have feature recognition but anytime you have too much automation you get automatic mistakes.
So, a CAM system is not a magic wand that you simply send your CAD model and BOOM, there is your CNC program. A CAM system is a tool just like all other software. You still need a human to interact and process the machining properly.
I have programed many parts with threads and I have not once needed modeled threads.
I hope that helps you.
Thanks what I needed, confirmation of what I had learned & seen in operation at the various machine shops I've visited.
I understand every system is different, but many of the concepts are shared. Just like 3D CAD, a CAM system is only as good as its operator/machinist.