I've never watched Steve Irwin, but I'm a member of the ECOLOG mailing list and lately my inbox has been filling up with ecologists' commentary on his approach to education and entertainment. Commenters seem to fall into two categories: those who admired Irwin and those who thought he wasn't serious enough, that his wildlife-based entertainment had little value.
I can't comment on Irwin specifically, but two assumptions came up often enough in the writings of the second group that I feel they must be discussed. The first is that respecting nature means taking a hands-off approach as much as possible. The second is that scientific research is intrinisically more valuable than, say, entertainment.
The title of the Charles Jonkel article linked to above, "Save a Grizzly, Visit a Library", exemplifies the first assumption. To a certain extent, I share it. Humans certainly are capable of harming nature and animals while enjoying them. But must I be a pair of eyes on a stick? While some of Steve Irwin's actions may certainly have been questionable, is there anything seriously wrong with my herpetology professor's lizard-catching or my munching on various woodland edibles? Promoters of the "hands-off" attitude often decry the fact that many modern kids learn more about nature from TV and computers than first-hand experience, but isn't this perfectly consistent with the "do not disturb" ethic? Under what circumstances may we participate in nature, and doesn't even posing the question separate us from the rest of the natural world?
Several list members have commented that handling, marking and sometimes even killing wild animals is justified only if it is for scientific purposes. Entertainment, even if educational, just isn't good enough. This claim is frequently followed by the assertion that the use of wild animals in research is acceptable because it helps with conservation or management. However, most zoological research has essentially nothing to do with conservation or management! While I agree that animal welfare is extremely important, I would argue that mist-netting 100 birds to band them is more problematic than capturing one or two such birds to show off on television. Furthermore, many (if not most) biologists chose their careers because they love nature and the outdoors. Biologists generally enjoy their work and this enjoyment is the primary motivation for the work. However, it is hard to argue that the satisfaction of a scientist's curiousity is inherently more worthwhile than the satisfaction of another person's desire for entertainment.
When animals are used in either science or entertainment, the animal's well-being must be paramount. Beyond that, it is hard to criticize Steve Irwin.