I found it! I still can't believe my eyes

So you cannot equip two weapon slots at the same time from Horrific Visions. So no main hand and off-hand. You can equip two Two-Hand as a Fury warrior tho.

What is a this backwards, idiotic design. There’s no sane argument for it.

/end of rant

It is indeed backwards since they literally recycled it from a previous (garbage) expansion.