Isnt't that highly dependent on the type and amount of explosive used in the IED? You really can't draw a conclusion like that based on that one series of photos!
Here's a photo of an M1A1 Abrams tank destroyed by an IED in Iraq. Are you going to claim that Humvees are less vunerable than those?
There are plenty of examples of fully destroyed Humvees, many much more so than in the video of the Chechen BTR you saw.
But it doesn't really matter anyway. My point is that if you want an armored vehicle, you design one or purchase one (such as a BTR). It's what a Humvee is not. Putting armor on a humvee destroys the speed and mobility that is what is was designed for.