I'm going to go out on a limb here, and say that I've seen most of Mark Sullivans films, and I have enjoyed watching them and have learned something from each one.
I'm not going to question the man's ethics as I wasn't there when these hunts and films were done.
I enjoy his tapes/DVD's for the close up camera work, the quality game which is taken, and the fact that a lot of double rifles are featured.
Usually, as soon as his name appears in any forum, a mob gathers, and starts ripping him apart.
I think maybe some are jealous/envious of MS's job, his fine doubles, his shooting ability, his nerves, and the fact that he's spent the last 16 seasons hunting/guiding in Africa with quality doubles.

Mark Sullivan regularly takes the hardest and most dangerous way of hunting and finishing off dangerous game, and his ethics are often brought into question by those who would seem to prefer an easier way of doing it.
Each to their own I say.
There are other ways to hunt DG than popping the best head from a big mob at 75 yards with a scoped boltgun IMO.