SethAZ 

It can be nonsense, certainly. In my own riding, what cadence I'm at is determined by the resistance I'm seeing due to the level of effort, which is influenced by my speed, ascent or descent, etc. There's no one cadence I'm shooting for, rather the cadence is matched to the level of effort. That being said, since most of my riding is in very flat terrain it's fairly predictable. If I'm going 12mph with my wife I'll probably be at like 60 or 65 rpm and freewheeling often with next to no effort or resistance in the pedals. If I'm cruising at 17 mph it'll probably be high 70s/low 80s. At 18 mph it'll probably be around 85ish, and at 19 or 20 I'm upper 80s to mid 90s. The higher 90-95 rpm cadences are only used when there's enough power being generated to develop significant pedaling resistance at a steady state. For non-steady state it's going to just depending on the conditions in each moment. I can't speak for anyone else, but for me personally spinning a high cadence can only be done at all if there's a pedaling resistance sufficient to justify it. Too-low resistance makes it actually difficult and senseless to try to spin a high cadence.

So yeah, I'm an advocate for reasonably high cadence (95 rpm is high cadence for me, may not be for others), but only as appropriate. I'll certainly never tell someone going 13 or 14mph on flat ground that they need to be spinning 90 rpm. That's nuts, and would probably have them flopping all over the saddle. I think your post is spot on in the sense that high or consistent cadence needs to be matched to the circumstances including the current level of effort, and aren't desirable under just any and all circumstances.