Let us dispense with this nonsense once, so that it need not be said again:

-Yes, fatbikes are necessarily heavier.  So are fat skis.  And larger paddle blades.

-If you mistake stable handling for sluggishness, you need to get out more.  And learn that the best way to steer a mountain bike usually involves the bars on a tertiary level only.

-If your understanding of riding in/on snow is such that 35c tires always work, you need to get out more.

-If your understanding of mountain biking is such that 2.2s always have enough float and traction, you need to get out more.

-If you think 8 psi is low as far as your fatbike is concerned, go apologize to your bike right now.

That is all.  Lots of people are riding fatbikes where another bike would do just fine, and making all manner of hyperbolic declarations of the sort humans are invariably subject to, especially where shiny things and the internet are involved.  But make no mistake, fatbikes are an innovation on par with disk brakes and suspension forks, and will prove more important than 29 inch wheels.