There is pretty good evidence that he lied on his way out of Liberia. Though I've not heard as to if he lied getting into the US... perhaps at the time Customs wasn't asking about travel in infected countries or close contact with infected persons.
Others say, he reported that he WAS in Africa recently around his sick cousin and the hospital just sent him home with a high fever anyways, and that they are at fault.
And this is something the hospital is investigating. There is a reason they call it 'practicing' medicine as it is unfortunately an imperfect field where imperfect humans are deeply involved with the diagnostic process... mistakes happen, as we see happened here.
Anyone with that high of a fever shouldn't be sent home, Ebola or not. Racial issues may be at the root of this botched care.
Who do you want to pay for that?
Unfortunately hospital resources are a limited one and their ability to admit everyone who is ill simply isn't possible. At last check, Duncan was without insurance for either of his trips to the US hospital, and the first time around they didn't think Ebola so released him with some antibiotics (not an uncommon thing with a fever when something more significant isn't suspected).
Ask yourself this... worst case lets say the first doctor was... a Grand Wizard of the KKK and said to himself "Black guy with Ebola... yeah, I'm going to get him on the street as fast as can be so he doesn't get treated and dies a horrible death"... do you think even he would be oblivious to the possibility of the infection spreading beyond just the initial person?
Someone f-ed up... and to blame racism is a ghastly thing.