Although there are many similarities between racing and touring bikes there are differences which make them more suited to the task at hand. Here are just a few of the differences:
1) Touring bikes have fittings to allow mounting of racks, bags, fenders, and even lighting systems;
2) Racing bikes tend to have more "upright" geometry that make them less comfortable, but handle and accelerate faster. Going to extremes, racing bikes can take constant attention to keep on the road due to extremely sensitive steering. They also tend to have a much shorter wheelbase and higher bottom bracket;
3) Touring bikes are built more rugged and often have "tested and true" component groups and parts that may no longer be used in the racing world. This is to increase the chance that if you have a failure in the middle of nowhere most places would be able to fix it;
4) Racing bikes tend to "push the envelope" when it comes to strength versus weight. Manufacturers assume that when you purchase a racing bike you know it won't last forever and accept the compromise in favor of high performance.
When considering a racing vs. touring bike try to imagine what you'll be using the bike for. Although it might be appealing to have a high performace bike outfitted for touring you'll soon discover that long trips are a drag and that everything wears out quicker. If you purchase a touring bike and plan to race on it it'll feel "clunky" and "soft" rather than putting your power to the ground.
This difference points to the constant controversy of weight versus comfort versus reliability. It is rare that you'll see all these attributes in one bike... for example, a carbon fiber frame is light and comfortable but one good crash and it is gone. An aluminum frame can be light, but it is can be very harsh riding and doesn't tolerate repair if needed. A steel frame can approach the light weight of carbon fiber, titanium, or aluminum and it has a classic ride combination of stiffness and comfort but a good one can be hard to find.
The biggest thing you can do is to ride every bike you can get your hands on and decide what is best for you.