Or they play public servers only because they can't/won't commit to the duties of a regiment. Since usually my regiment scheduled events are mostly on weekends, I'd gladly play some public games in the week days. However, knowing for a fact that they're like playing lottery, and you'll only have a decent skilled officer when you're very lucky, and most of the times it'll be a rambo, troll, music on the speakers, random charges fest, for me it's a thanks but no thanks.
I don't know why anybody would pay for WoR only to not play it like a unit, being a game TOTALLY focused on that playstyle. But I do can imagine people leaving the game after experiencing a few public games which weren't at all what they had imagined the game would be. There is a reson why most Youtube videos on the game feature cool, disciplined, regiment games, and not anarchic public games.