It's an interesting dynamic in rugby. All AB front-rowers have an enforcer portfolio, and that can lead to them being thugs - from this incident, to Woodcock v Fainga'a, to Mealamu on O'Driscoll, to the Franks brothers' lead-with-the-forehead tackles, to Fitzpatrick's and Loe's entire careers. The same is true of other countries I'm sure, I just don't pay the same attention.
The standard response is that there is a difference between big men putting on a bit of niggle, and one bloke belting another in the back of the head - and that is true, and that is why Hore should be banned for quite a long time. But the difference is really one of scale rather than type, so I find a lot of the moral outrage over this to be fairly confected.
Hore is a thug, but he plays a game where the line between Brad Thorn and Martin Johnson is a finer one than many care to admit. In NZ at least (and England too, while we're at it) there either needs to be less hero-worship of "hard" players - to the detriment of the game - or this has to be regrettably expected occasionally.