hahaha so funny how ppl get angry when someone simply pwns them ...
It's single player/co-op content. There is no "pwning." You either have the gear to do this or you don't. Only so many people can have the gear simply because of how item affixes roll. His gear literally has some of the best affix rolls possible, and there aren't going to be many of them out there in this great of combination. If he sold his set to someone else, they could literally do the exact same thing he is doing. Sure it's cool to watch, but it's not a measure of skill. He isn't going to die due to life leech with the damage output, and he doesn't need to move, he just needs to stand in one place and click. There's no dodging, no planning, nothing outside of spamming a huge damage move with the gear.
What you see as anger is really people saying, "meh."
Its not OP, before anyone starts to whine. He is a good player because. He got the best items you can get and he experiments with a build, while everyone else copy pastes the WW builds.
There are really not that many variations to play with. There are a lot of abilities and passives, but very few core abilities. Those don't change, only the last few do. He's using Thrive on Chaos and Weapon Throw. These aren't new builds. I was running a life% on hit build with Furious Charge+Dreadnought, Overpower+Revel, and Revenge+Provocation, with Pound of Flesh. It worked really well for quite a while, but to handle the increased damage of higher MPs, I had to switch to something else, so I invested in more life% on gear, got myself to 100k hitpoints, and switched to Whirlwind+Blood Funnel and Inspiring Presence. I still use Furious Charge+Dreadnought for the movability, but changed Revel to Killing Spree to support my life gain. Now are you going to call that a classic Whirlwind build? Because when everyone else was doing Whirlwind+Sprint, I was doing the first build I listed, because that's what I enjoyed, and this new whirlwind build for me is what I enjoy now -- it's what works for me.
People aren't "copying" as much as you think. They are choosing what they like, just like Dex is doing -- that 100th spear weapon dropped so he decided to try a weapon throw build. It's called adapting to the situations around you ;-)