He/she might not have put the snake there, but it was well within their power to simply reach out, take the snake, and put it safely away. It wouldn't have been much of a stretch at all, well within anyone's physical capabilities. It's not something that would've taken them twenty minutes, or even one. Just a simple moment, and this whole fiasco would've been avoided. Instead, they chose to simply film and then post it on YouTube for the giggles and views.
And yes, while a lot more gruesome things happen out in nature everyday, this was happening right in front of someone who had the power to stop it. The bird didn't need to kill that snake, since they were obviously in no danger and most likely had food, so it wasn't like the chick needed to kill the bird to survive.