The reason people try to blame the parents is because of their own fears. They think if they can find some nitpicky thing the parent did wrong, then they can delude themselves that they were in that situation they could have done something different to prevent it. Which is asinine.
I think a lot of the anger people have now, especially toward the parents, is because now all of a sudden there is something else to be afraid of that they never thought of before. You can't predict everything that can possibly happen. The only way to completely avoid alligators is to never be in their habitat, in other words, don't ever go to Disneyworld.
This parent was walking his son in water that was shallow and clear at the edge of the shore. Of course he didn't think there was an alligator lurking nearby, or he wouldn't have let his son be in that area. And of course Disney didn't think it would happen either, or they would have taken further precautions. They thought they were pulling all the alligators. Well, it's a big lake, and a few slipped by them. Think about it, that is a huge body of water, and they only found 5 alligators - anywhere else there would have been dozens of them, at least.
The only way I'm going to listen to anyone trying to blame the parents is if they post a video of themselves telling their own kids to stay away from the shoreline in case there's an alligator from before this incident happened. There isn't one anywhere in the world or it would already have been posted and gone viral.
You're trying to make yourself feel better, feel like you would be in control in an uncontrollable situation, that's all you're doing when you're trying to blame the parent. You think somehow you'll be able to protect your child from everything? I'm sorry to give you the wake up call, but you're wrong.