Its def. worse than what Ironforge.pro shows. They only take data from the ppl that raid. I can promise you a big chunk of pvpers never steps a foot into any of these raids.
Also there were some recent free character transfers I believe around the time TBC or so hit.
On IF. Pro said server looked balanced but the free character transfer from blizzard only allowed horde players to leave.
IF Pro is def. not accurate when it comes to pvp numbers
here:
They allowed free character transfers from faerlina on both sides, but horde only from whitemane to another server.
Ironforge pro lists faerlina and Whitemane as equally balanced.
We know the numbers are not correct.