Last time a I checked, no one has died of neglect in an American hospital.
How did you check this?
Well even assuming it's correct (which it very certainly isn't), it doesn't tell you anything about the people that die of neglect because they aren't treated to begin with.
I was under the impressions American hospitals were legally obligated to treat people and the bill was to be dealt with afterwards.
This is entirely correct. One is much less likely to suffer severe neglect or ill-treatment before or during care relative to the situation one often ends up in after.