Leg Shot roots for 5 seconds: http://www.torhead.com/ability/1KgmaGG/leg-shot
It's instant, has no GCD, and has only a 15 second cooldown.
It's on a class with multiple knockbacks and a snare AND can't be the target of Force Leap while in cover.
So Knights are Forced to slog through the snare, dps, knockbacks which all give very little Resolve, then get Rooted which ignores the Resolve bar.
5 seconds is ample time to get some range and breathing room to start the snaring process all over again.
So no it's not a "misnomer". And by neglecting to take into consideration the plethora of other CC available to just this one class/spec you are missing the big picture.
When you factor in the CC available to all classes it's makes for PvP with an excessive amount of CC and it's the crux of the disparity between melee and ranged classes.