It is capitalism. So was the gouging after Katrina. In a free market economy, the owner or producer of a good or service is free to set the price however they see fit in order to maximize profit. In a competitive market, that profit motive often times reduces the price due to competition. This makes companies operate more efficiently to lower costs and maximize profits. This drives an economy to run as efficiently as possible, something other economic systems can't do. The problem in this case is that's it's pure free market capitalism without a competitive market place. Capitalism makes no distinction between goods or services that are needed vs. those that are merely wanted. Normally it's not a problem because the free market will draw competition to an overpriced area, product, or service. But in short-term cases like disasters, that doesn't happen quickly enough.
This is why no country has a pure, unabashed, unregulated free market economy and why certain goods and services are regulated more than others. Even Hong Kong, one of the closest to pure free market capitalism in the world, has recently added a minimum wage law.