"...these conventions require a devotion that is fanatical."
The JW conventions are intended to whip up fanatical devotion to the borg also, the difference is that whilst at the convention JWs show their fanaticism on the inside then go home and shun the crap out of any who are not as fanatical as them. I'd guess that most that go these political conventions are fanatical whilst there, then, go home and are normal people again.
Either way aren't all conventions intended to do the same thing - whip people into a frenzy of blind devotion however they go about it?