Ok, an Aussie's viewpoint. I didn't see the youtube video before it was taken down, so this is pretty limited, and only my viewpoint (hope my facts are right).
Feral cattle, camels and buffalo. As per the name, all of them are feral, killing off any of them would be good.
Regarding the buffalo, I think we introduced some sort of virus into the population, so now it's more making sure that the herds don't get too large again. They cause problems, but given the relatively low numbers, there're worse problems.
The camels don't cause as much destruction as the others, but are still problems. I recall something about us having the largest feral camel population in the world, and some stuff about us exporting some back to the Middle East as breeding stock and maybe food (?), so I'd say they're edible as long as they're disease free and all the usual stuff. Numbers are more the problem, slightly compensated by the fact that they don't do as much damage.
Not really up to date on feral cattle or deer though, so I can't say anything there.
As for the roos, look great, and pretty tasty too! Funny how we're the only country to eat the animals on its national crest (I think). That said, populations are massive in some areas, and they can cause problems for the farmers. Even more so since we're recovering from/still in a drought depending on where you are. Some people don't like it, but I figure it's got to happen otherwise the farmers are stuffed. Hunting roos is regulated like everything else, and only certain species are harvested, others are on various endangered lists and all. Also need permission from the landowner if you'll be hunting on private property, so as long as he's hunting the right species in the right areas, he's helping out the farmers. Selling the pelts and meat is possible, not sure how much it fetches though.
All that's well and good, but from my viewpoint, it's more interesting to note the animals not mentioned on the CS webpage (haven't seen the video, so I can't really say that he didn't hunt them). The bigger problems facing us are, IMO, the feral rabbits and wild boar. The rabbits eat everything, destabilise the soil and breed like... well, rabbits! The boars eat stuff (and account for a fair amount of the lambs lost), cause erosion, foul water supplies, and so on. Admittedly taking 120 rabbits will make less of a dent in the population, but it's still the bigger problem.
If they weren't hunted, I can't say why they weren't. But that said, boars are the same the world over, nasty buggers if you piss one off, as you could probably guess. Regarding the rabbits, well, I can't really see anyone wanting to buy a video of Lynn hunting rabbits.
All that said, if any of the other Aussies are reading this and I've said something wrong, please say!