Dude that forum thing was from 2008. Times change and so do their policies. You agreed to their terms and conditions, one of them being that you accept that said terms and conditions are subject to change.
This has already been addressed in another now locked thread because childish tantrums are absolutely unconstructive.
https://us.forums.blizzard.com/en/wow/t/multiboxing-question/707820/29?u=leilleath-moon-guard
You agreed when you paid for your subscription. They’ve already said there will be a grace period with warnings given rather than bans. If you’re playing with appropriate software and methods, you have nothing to fear.