If that's your argument, then the courts must not either. In the various cases that the federal government has been taken to court over interpretations of the Preamble, most rulings have tended to side with limiting government.
United States v. Kinnebrew Motor Co. is an example of this. The government tried to argue that interstate commerce included fixing the price of what cars could be sold at, but the courts struck down this interpretation.
The courts have upheld somewhat broad interpretations of things like eminent domain (like the Supreme Court ruling for Kelo v. New London), but most of the time, federal courts err on the side of limiting government. Now, state governments typically have a lot more latitude than the federal government to intervene on various things. This goes back to the principle of federalism. Not surprisingly, eminent domain is usually applicable to state or city governments, not the federal government.
