Well, technically..it's not really unfair as all clans can do the same.
But yea, it's quite unfit to call 'Clan system' if everyone including non-clan members stats are also counted. It's becoming more like a unofficial gang instead. However, I dont really want to limit the ability and freedom of clans system based on my opinion alone, especially as it is unlikely to affect other clans as they can also do they same. So, i personally think it's best to see the players view on this. If you think it's not fine, you may post suggestion and let other players vote.
The votes can help us to decide but it does not mean we will directly accept it without further check. If the management find better reason to keep/change current system, we will choose the best one.