My first exposure to the GUE happened about the same time I joined ScubaBoard ... but the source was local. My ex-wife and I were doing a dive at a local site and noticed a couple of fellows with some gear that looked different than what we were using. So my wife asked them what it was. Rather than answer, they simply snickered, told us we were accidents waiting to happen, and advised us to "ditch the snorkel". We later discovered they were part of a larger group of GUE divers who met regularly to dive this site, and that they had a reputation for being vocal to OW students about how badly they were being trained. The rest of the dive community referred to them as "the posse".
Fast forward 15 years ... only one of those fellows is even still diving. The rest are now off being "the best" at other recreational activities, and I don't doubt that they're still exhibiting the same attitudes in those sports as they did with scuba diving.
I don't think that GUE, in and of itself, encourages arrogance ... I think rather that it attracts the sort of personality that's prone to it ...
... Bob (Grateful Diver)