I think it is. I think guilds on RP servers can either be hugely important social groupings for people (I've been in the same guild with one name change since release), or entirely trashy throwaway devices that let you put amusing and sometimes witty remarks under your name (<floorwarmers incorporated> is my favourite on ER at the moment).
Is this an RP server thing perhaps? AD and ER were the original 2 EU RP servers and it sounds like the 2 communities are very similar (although I've not seen a joke guild with quite as good a name as <and two stealthed rogues>).
In the former case, the effects of people leaving can be quite dramatic. Way back, not that long after EU release, and just at the point where there were enough level 60's around to start raiding seriously on our server, the currently most progressed Naxx guild on Earthen Ring formed.
I remember the absolute HOWLS of outrage that came up from members of the smaller guilds when their two or three level 60 players were "poached" to join that raid guild. There were literally people who refused to talk to former guildies who they felt had betrayed them and their original guild. Even to this day, now approaching two years on, there are people who look down on that guild because of how they formed and because what sticks in the memory is how some of their guildies left them to join a 'non RP focused' guild. It's really quite bizarre to observe sometimes!