That said... isn't the whole appeal of 120Hz simply the fact that it's evenly divisible by both 60fps and 24fps so that you can avoid jittery 3:2 pulldown when presenting film-sourced content? In other words it's not that 120Hz is desirable on its face, but that it's good to be able to display 24fps content without molesting it.
That's certainly a factor, and explains why "120" and not "100" or "150". On the other hand, most people can discern the 60Hz flicker of older fluorescent lamps - and in Europe the 50Hz flicker can be disturbing. Televisions with 100Hz refresh have been common in Europe for 15 years or more.
If you've seen a demo of 120Hz vs 60Hz, the difference can be dramatic. Any scene with moving straight lines is vastly better at 120Hz. For example, I saw a split screen of moving text (like the original Star Wars movie intro). The 60Hz side was basically unreadable - the 120Hz side was smooth and perfect.
I'm not sure the existence of 120Hz displays really makes your point.
Of course you're right - but a common technique in debating is to bring up a fact that clearly contradicts a claim of the other side.
Call one point into question, and you make the reader wonder about the whole argument.