I feel horrible for this family as well, just horrible. I can't imagine losing my son (and second on the way) - particularly in a manner like this. They are undoubtedly feeling immense pain.
That said, given this initial report, you have to conclude they were contributorily / comparatively negligent (I don't know what kind of jurisdiction Florida is). Signs were posted about the gators as well as signs posted warning not to swim. It is tragic, but some of the responsibility lies with the parents.
I also don't like that we've become a victim society. We feel when someone dies that there has to be someone else responsible or to blame. Sometimes, tragic accidents just happen.
Also, wildlife is not doing too well across the world due to habitat loss, pollution, etc. We're in a period of mass extinction that is unprecedented caused by humanities' actions. I hope Disney doesn't respond with draconian measures just to sterilize the place and kill all living things as has been suggested. The prospect of liability has led to the demise of a lot of natural habitat and critters across the world and I hope this doesn't become another example. I'm certainly not putting animal life above human life, but hope no overreaction occurs.
Still, what a horrible tragedy. Very sad.