If we want to fight Ebola we (the world) should be sending resources to where the outbreaks are occurring and helping those poor people. Ebola is difficult to transmit, closing our borders to the infected countries isn't the solution. Though... it might not be a bad temporary one until the outbreaks are under control.
The largest problem is that both Liberia and Sierra Leone where the outbreaks are the worst only recently came out of civil wars and their health care systems pretty much suck dog shit --- 2 doctors care for like 100,000 people. Yeah. It's that bad. That's probably the biggest problem... The WHO is just an organization and can't be expected to step in and take care of an entire country every time shit hits the fan, the countries themselves need to step up.
Health care workers that are fighting it haven't even been getting paid by their governments and many are going on strike because of it. So, money's the biggest issue. People aren't even getting the hazard pay that they were promised.
The World Health Organization isn't exactly a shining beacon of hope though... They were completely caught off guard and are even quoted as saying "We don't understand why the virus is spreading so quickly, we all underestimated the complexity of the outbreak, how this would play out in a country where it has very little capacity." At the moment I think they're generally being overly optimistic in regards to dealing with the outbreak. I don't think it will be nearly as easy as they think.
Just to address what you brought up in your opening post though... People that are infected and return to the US generally aren't "patients" because we screen for it before they get on the plane and again after they get off the plane. The symptoms show up afterwords. The big problem that happened here is that the doctors were too dismissive and sent the guy home once the symptoms appeared and the disease was transmittable and he came into contact with a whole variety of healthcare people and likely others in that time where he should have been contained, especially having told them that he came from Liberia. They sent the guy home with a 103°F fever, who does that?
While people are fairly optimistic about how easily we'll contain it I don't think it'll be quite so easy to contain and quite a few more people are going to end up sick or dead before this is over but it's not like we'll see a US epidemic or pandemic. It won't get anywhere near that level.
edit: To expand upon my first few sentences... I don't think we should be closing our borders entirely but we should be enacting quarantine procedures for anyone returning from those countries until we're satisfied they aren't infected. I also do think that people should be allowed, in quarantine, to return to their native countries to seek treatment because let's be honest about this... leaving them in those shit countries with healthcare that subpar is pretty much consigning them to death. Worst of all is that most of the people that are going to get infected are likely the ones over there trying to help fight the disease, good people -- not exactly some troublemaker trying to screw you over and doom us all.
