They weren't exploiting anything, they used lazypig which uses /script JoinBattlefield(1) to queue and automatically queue you as a group
http://wowwiki.wikia.com/API_JoinBattlefield
It is your fault, devs of nost, that the group queue API is or were still there, on ED the developers actually knew how to remove it and did it before releasing AV.
I didn't see the bugtracker even once but I know stuff has been reported and you have not fixed them.
Don't blame this on the players, it is your fault, developers, nothing has been exploited.
Your bans on these players are unjustful, also, Group queueing is blizzlike, we used to do this in retail vanilla... I was like 11-12yo and I still remember it clearly.
You cannot blame these guilds for this, nor accuse them for withholding information.