Becuase in inferno it is required with your builds? specially if you grab double resist gear
I am in Inferno (Start of Act 3). I don't see how it's required. As long as you can keep your resists within like...100 of each other, there really is no reason to use this passive. It also frees up gear options, so you don't need to continually hunt for 'x' resist. While the AH certainly helps remedy this, being able to find things easily, it certainly doesn't help when you find something that is somewhat worse than what you have, but simply double-dips in 'x' resist.
@EzCheez: Regardless, Resists, Dodge and Armor all hit DR. And aside from Fists of Thunder, and Mantra of Evasion, you don't really need Cyclone Strike since by that time it's going to give you like...3% dodge; oh boy. You can easily run a 60%~ dodge, with 300+~ resists, 4000~ armor and 45k+ health build, WITHOUT One With Everything.
@DogFishHead: I mean, I don't know about you, but I have 3 friends. Are there certain packs where it does feel like Monk (and Barbs) are not very effective? Yes. But there are also packs where DH and Wizards can feel the same. It is possible for someone to be in Inferno as this class and not be having the trouble you seem to be having. There are some issues, but it certainly isn't "THIS IS HORRIBLE, THIS IS THE WORST CLASS" type of issues that everyone is acting like. I'd like to think that increasing the damage enemies take by 24%(48%) makes me a valuable party member, as well as acting like a off-tank/kiter, but still maintaining respectable damage.
Also, to make my comment clear. I am in no way saying it's not an effective or a good choice. However it's not a "YOU MUST HAVE THIS IN ORDER TO DO ANYTHING" passive.