Many observers, from the International Monetary Fund to Virgin’s Richard Branson, say the stock market is overreacting to the oil-price shock. (Crude closed at $26.21 on Wednesday.) The basic argument is that the energy sector (oil and gas are about 2% of GDP) is too small to drag down the overall economy. We’ve heard this kind of argument before. When house prices and new home construction began to tank in 2006, some observers told…