Doesn't actually prove anything, but it's fun to watch.
As pointless as it is to argue with strangers on the internet, this time around it will be especially pointless. That's because, in the video you're about to see, Automobile magazine isn't really making a straight-up comparison. Each of these cars has been built for very different purposes, and more importantly, different price points. There exist versions of these cars which could be compared, but that would be less exciting.
That's really what's going on here, the Hellcat is exciting, the Z/28 is exciting in a different way, and although the Mustang is too new for any of the really crazy versions to be out yet, its newness is still exciting. So there's no really point comparing them, but it's to fun anyway.