http://travel.state.gov/content/pass...ntry/cuba.html
You are free to go to Cuba. And have been for years.
This from your own link:What part of Tourists travel is restricted for US citizens do you not understand.?
TOURIST VISA REQUIRED:
Tourist travel to Cuba is prohibited under U.S. law for U.S. citizens and others under U.S. jurisdiction.
http://gocaribbean.about.com/od/cuba...226e6-0-ab_msb
The U.S. government has limited travel to Cuba since 1960, after Fidel Castro came to power. The American government has essentially limited sanctioned travel to journalists, academics, government officials, those with immediate family members living on the island and others licensed by the Treasury Department. In 2011, these rules were amended to allow all Americans to visit Cuba as long as they are taking part in a "people-to-people" tour. Independent travel to Cuba by Americans -- and specifically, spending money there -- remains prohibited, however.
Authorized travel to Cuba typically takes place via charter flights from Miami, since scheduled flights by U.S. airlines are illegal. Cost of the short flight typically exceeds $500 per round trip.
It is illegal for any U.S. visitors to bring back any purchased goods from Cuba, such as cigars. It also is illegal to contribute to the Cuban economy in any way, such as by paying for a hotel room.