Do you realize that when a third world nation becomes destabilized by a natural disaster that it becomes a threat to the nations surrounding it? How?
Well let us first look at the issue of CRIME! Third world nations are already largely crime infested. They are havens for human traffickers, pirates, terrorists, drug traffickers, and arms dealers. These are international crimes. Haiti is a stepping stone for them and chaos...ANY chaos further shields their activity from our view making it easier for them to access us. It also serves them to draw those who would normally be law abiding poor into their illicit activities because it pays something back because their lives are already in great risk from starvation.
More CRIME! When these people choose to try and escape this island whether by methods of being smuggled into our country or using life rafts/inflated tubes to get here, they are under the status of an illegal alien. Because the majority of viable jobs require you (read, write, speak english, be able to produce an SSI number for taxation purposes and residency proofs) they are left to either sweatshops (which are feeding an illegal market), under the table odd jobs, or (theft, dealing drugs, prostitution, fraud), and then there is WELFARE FRAUD.
There is always the threat that those who were in power will not be in power after a disaster. Because tensions run so high in third world nations (and Haiti had an issue with rebels as it was) the balance of powers and who holds the sway of the masses can easily change and it could easily be someone who could offer hostility to our nation. They may not be able to harm us themselves but they may allow those who can to occupy a military base there. Cuba and its missal crisis is a good example of that very condition.
CITIZENS OF HAITIAN ORIGIN! They are tax payers and they do have loved ones there that want help. Because they pay taxes they have the right to expect the government to aid them!
US Citizens are trapped! Yes! We had tax paying citizens who were there for a multitude of reasons. They were missionaries, vacationers, businessmen, and government officials. They have every right to expect aid is on the way. Their families have every right to expect them to receive aid and be recovered dead or alive!
DISEASE! This is serious. Germs don't stay in one place. In fact bacteria and viral agents mutate swiftly. (I know the argument is going to be that disease existed there before but you must take this into account) - disease that is growing on a dead body is under pressure to find a living host so that it can continue to proliferate as any living organism would. This means the chances for mutation raise. When a disease mutates it may not respond to traditional treatments, can infect wildlife, and spread via new means (a germ that was once spread via contact is now spread via air). Because insects and animals are attracted to dead bodies they become potential carriers. Birds, insects, bat, rats, mice can travel hundreds of miles and across oceans by various means. That makes disease a threat to our populace. Now keep in mind we have rescue workers there and victims who need to be returned to their state origin. Humans carry disease also and can infect others here if we do not contain the devastation now.
Economic Interest! All the money gathered is immediately dumped back into the world economy. Those tents, food,water, medicine, medical equipment is not free. It is purchased. This makes things better for the US economically even if the money is not going necessarily to US businesses.
This is what reasonable people call social responsibility. It has nothing to do with morality. It is in the best interests of our citizens. The tax dollars we pay year round go into a fund for rescue purposes so there is no addition to the deficit everyone is worried about.