Cool video, thanks for putting that up.
I believe the problem (if you choose to view it as such) with their testing methodology is that they put the gel within inches of the wall. The dispersal of the lead shot happens at the exit, or after a ricochet (capsule compresses on entry, "explodes" apart on exit. But, like a shotgun, it takes some time for the shot to disperse; more than a couple inches I'd presume.
I think it would be really cool to see tests like those with an ultra high-speed camera, with the gel placed at a couple inches, out to a yard or so, in 4-6" increments.
IMO, it would take something on the order of planetary alignment to have a defense shot gone wild, or an accidental discharge, whack someone who happens to be standing within inches of a wall at the point of exit.
By the way, the "ball" they remove is the component making up the snoot of the bullet for more reliable feeding.
All-in-all, I think I'd rather still use Glasers than a good defense hollow-point for in the home
(I'm in a townhouse, one neighbor, multiple layers of 3/4 sheet rock and dense insulation - firewall). Hornady makes a point to exhibit the FBI penetration testing where the slug is still intact and lethal (as defined by the FBI) after perforating drywall, glass, wood, etc.
For a walking around mag or speed-loader load, I use a couple Glasers on the top of the stack (penetration not needed for an "immediate threat") and, depending on the firearm, followed by Hornady, Silvertips, HydraShock, or COR-BON.