Because DW is in a no win situation due to greedy lawyers. If they had the sign no swimming and no lifeguard, if someone drowned the greedy shark lawyers would sue DW for not having a lifeguard on duty.
One of the locals was quoted saying that at night it looks like Jurassic Park in that area.
Gators feed at night. If that kid was 2' off shore wading and splashing, he was making live bait noises right in front of a predatory reptile more than capable of taking him whole, as we see. They might as well have dragged a whole chicken back and forth in the water.
Recall the article Machiavelli posted here just a couple of weeks ago, about Florida Fish & Wildlife confirming they have caught three Nile Crocodiles in the Florida Everglades in the past few years. Crocs are even bigger and much more aggressive than a gator ever dreamed of being. A croc can take a whole wildebeest; it should be no surprise to anyone at DW that a gator can easily take a toddler.
That lifeguard could not possibly have been prepared to deal with something like this. I see big lawsuits with enormous cash awards for Mom and Dad. Never mind that they let their 2 year old kid go wading with the alligators in the first place.
"Stupidity cannot be cured with money, or through education, or by legislation. Stupidity is not a sin, the victim can't help being stupid. But stupidity is the only universal capital crime: the sentence is death, there is no appeal, and execution is carried out automatically and without pity." -- Robert A. Heinlein, Time Enough For Love
This time, Mom and Dad being stupid cost little Junior his life. chomp, chomp....