Pythons are extremely invasive species. Where they came from, wild life isn't very abundant which is why villagers hunt and cook them. In Everglades there's ton of animals. They eat everything. One large female python can carry up to 100 eggs. In animal rich environment they spread like wild fire. Messing with ecosystem.
One stray python won't easily overcome adult human, hundreds of them lurking in the swamp will go for humans when they deplete other food sources including gators.
Given enough food, large female python python will reach 5.5m (18ft) and 70+ kg. Can easily kill a child. Those animals are no joke.