I'm surprised at how surprised everyone is - when my wife told me this yesterday, all I could think was, "I'm surprised it took this long." Irwin clearly loved animals, and his enthusiasm was infectious, but I never got the idea that he respected dangerous animals, or at least respected their power. This reminds me of the death of the "grizzly man" a few years back - same mindset. I feel very bad for his family.
If there was something surprising in this, as others here have mentioned, it's in the animal that killed him - sting rays are brought out at aquariums for kids to pet! Just goes to show, if you annoy even the most innocuous creature enough...