While there are legitimate questions about the potential severity of swine flu, it is still a dangerous flu for a simple reason - most flu viruses in circulation are very minor variations on existing strains, which means that most people who get the "flu" end up with symptoms that have more to do with histimine reactions - runny eyes and nose, aching joints, maybe a day in bed feeling lousy - then they're past it.
Swine flu, otherwise known for its genetic markers as H1N1, isn't an existing, commonly circulating flu. It's relatively new although with very old antecedents, which means that most people have no immunity to it. This means that it will likely spread remarkably quickly, will leave a significant portion of the population sick with it, and could prove to be deadly even for adults.
What epidemiologists are discovering about this particular flu bug is very disturbing - first, that it is a variant of the Spanish Flu virus that accounted for more deaths worldwide than World War I, which was waging at the time. Spanish flu was extraordinarily virulent, and when it finally died out, it became very quiescent - effectively disappearing altogether from the cloud of seasonal viruses that normally lay people low in late winter.
However, in addition to this, it now appears that the term Swine Flu is more apt than was even apparent on the surface - Swine flu itself first appeared in hog factory farms in the 1990s, mutating rapidly in the high density "population" of pigs kept in tiny pens little larger than the pigs themselves. The flu wasn't lethal for pigs, and the particular strain of swine flu that did jump to humans was of a variant that didn't "catch", failing to reach critical mass or virulence to be a true pandemic.
The early 1990s also saw the graduation of a crop of new business school MBAs, instilled with a twin philosophy - automation was the wave of the future, and one could apply the new thinking of the 1980s to every business endeavor in order to transform these into hyper-efficient super businesses, including agriculture. "Archaic" farms that had established an understanding of animal husbandry over centuries were quickly put out of business and bought out by new "factory farms" that used a combination of technology, mass-injections of antibiotics, close-confinement of the "stock" and waste disposal being passed to the community.
The last issue eventually caused enough of a reaction that many of the now very wealthy agribusiness concerns realized that setting up factory farms in Mexico, which had far laxer environmental laws, lower labor costs and generally a less empowered populace, might actually prove more profitable (just as such farms had tended to relocate in states that had lower taxes, environmental restrictions and wages originally).
In the end, this strategy, while increasing the overall production of beef, pigs and chickens dramatically, also caused the price of these meats to drop fairly dramatically, further eroding the ability of other farms to compete and driving them out of business. Meanwhile, south of the Rio Grande, these elongated factory farms proved the ideal breeding ground for increasingly antibiotic strains of viruses. It was only a matter of time before such a strain would jump to humans (indeed, it's likely that Mexican workers at these plants were also virus laboratories, providing many more opportunities for animal to human transmission), and from there, additional vectors took it into the general population - other kids playing with the infected kids bringing home the virus usually without knowing they had it.
The epidemiology of viruses is well known, yet advanced knowledge of medicine isn't going to help when you have viral factories that speed up the evolution of viruses a thousand fold. Even if this particular virus proves not to be especially virulent, the next one or the one after that may well be. Perhaps it is time for us to start questioning whether the factory farms are in fact yet another artifact of the "greed is good" mentality that's proving to be so destructive to the rest of society. Beyond the ethical dilemmas of keeping animals in such conditions, these factory farms are increasingly proving to be businesses that do harm than good, and as such at a minimum need to be rethought in light of that, and perhaps even need to be abolished (not just moved to places where people can't protest them).