I think he states it pretty well. The use of lines in wrecks was contorversial, in part because it allowed recent arrivals to make penetrations that would have taken years to acheive with progressive penetration and I think much of the objection from the wreck community was along the lines of cave divers using lines getting spetacular penetrations in short order and in essence not "paying their dues" so to speak. Progressive wreck penetration obviously favors the local zip code diver and for the NE wreck divers, cave divers were just visitors. I don't think it is much of an issue anymore.
Conservation is indeed a big issue. Cave divers are trained from the start to have as little impact on the cave as possible, with perfect bouyancy, no contact, leave no marks, etc. There is a definite anbd agreed upon understanding in the cave community that caves take thousands if not millions of years to replace so what we have is all we are ever going to have.
There is some variance as some cave divers don't really give it the focus they should (IMHO). In N FL this September I saw some incredibly deep hand and gouge marks in what were recently flooded and fairly fresh cave floors. There are sadly way too many cave divers who skills frankly suck and should stay out of the cave environment until they improve, or care enough not to engage in what amounts to slob diving. (But to be fair, in the wreck community, no one would notice.) From a slightly different direction, In many caves where scooters are used, you can see shroud shaped gouges in the silt or clay on the floor and damage to the ceiling from tank impacts is common - as are many posts made by cave divers saying something to the effect "Me and my buddy were 4000' back in XXXX in a low bedding plane when he caromed off the ceiling and silted out the whole cave". (Not to bash all scooter divers, but the conservation ethics and expectations surrounding the practice in general could be improved - and oddly it is usually the buddy who screwed up, so I suspect there is at least some guilt over the damage.)
In any case, in the cave community your reputation in large part depends on your skills at leaving a cave untouched and in upholding a very strong conservation ethic. It gets fuzzy when divers start sacrificing that principle in pursuit of longer pentration and exploration (and/or the bragging rights that come with it) that a few feel overrides the needs for conservation.
In the wreck commnity, bragging rights seems to come from how much crap you have brought up from any given wreck. The argument is that the sea is rusting everything away and if divers do not "salvage" it, it will be lost forever. That was probably true when there were very few wreck divers and very few diving below 100-130', where only a hand full of divers would ever see a given artifact on a deeper wreck, but it is hard to make that arguement and have it sound credible today. I think to some extent the ethics in the wreck community will change and perhaps are changing to some degree, but there are still strong undertones of "get it before someone else does" so any true change will require a truce of sorts where everyone agrees to leave stuff in place for future divers to enjoy.
Wrecks are also limited in the respect that major ship wrecks in diveable waters are now very rare to due to improved navigation, improved weather forecasting, improved salvage capabilities and the lack of a world war for the last 65 years. At some point the wreck community will have to acknowledge that wrecks (other than rather uninteresting artifical reefs) are a non-renewable resource and that damaging the wreck and the accretions that protect it to remove artifacts speeds the deterioration of a wreck, particularly with ever larger numbers of divers on them.
All of that is said from the perspective of a wreck diver turned cave diver, who prefers the latter by a large margin, so it has a definite bias to it. But the probable comments on those remarks may shed some more light on the motivational differneces and differences in priorities between the wreck and cave community.
Solo diving is not quite as clear cut as boulderjohn suggests. DIR/GUE/UTD divers will pretty much avoid solo diving on general principel whether it is in a wreck or a cave. Some wreck divers will see benefits to the team and also to the solo approach depending on the situation and the same is true for some cave divers. For example, dives in very tight and silty tunnels may be dives where some cave divers may prefer to be solo as getting out may be quicker and or easier solo than in a team. There is probably more variation with in the cave and the wreck communities on this issue than between the cave and wreck communities.
