I've noticed this too, mainly because I've been a group leader before, and still am.
Let me try to explain:
It's a war.
All it is, is a war.
Group leaders are ALWAYS fighting over members, so that they become the most popular, active, largest group.
From what I've noticed, most group leaders don't even care about RPing much anymore.
All they care about is the numbers.
It's like in middle/highschools (from what I've heard).
Most popular kids aren't even being themselves, they're using a fake front to try and become popular, even if they don't care.
It's the fact that they hold the title of 'popular' that makes it worth giving up yourself.
It's similar with /most/ group leaders.
They pretend that their group is active and fully literate.
I've joined RPs where the group/group leader NEVER RPs!
They just sit there and chat the entire time.
It's what happened to TWR.
They took the 'Best WC Group!' 'Most Active and Popular WC RP!' and other praises too highly.
When I joined towards the peak of their RP, I sat in the map for 3 HOURS and never RPed, only OOC.
TWR claimed to be the best, most active, literate RP there is, but they don't even RP.
They put up a fake front to make themselves seem cooler.
Back to the topic at hand, it has to do with what's above.
Group leaders see how many members they can get to waste 2 or 3 hours sitting by them, just to never RP.
When a group leader notices another of the same has called out upon a piece of 'valuable' member space, they MUST take it from them.
They have to get that member, or else that other clan will become better than them!
So, they ask the same person to get them to join their clan and not that other one.
But, leader A, who asked first, gets angry because leader B is taking their member.
So a war starts.
While group leaders many not think about this, it's really what's going on.
Me, along with quite a few of my group leader friends, try to avoid this.
We made an RP to RP, if we get 5 members or 36 doesn't matter.
We're RPing? Great! That's what I want.
But from what I've seen, others don't think the same.
They want to become the most popular, most active group there is for bragging rights, nothing more.
And because of this, wars break out.
That's the best answer I can give you, and it's also kinda a rant.
So sorry. XD