Open market economy

For many years I have been incredulous about the so called open market economy. If the economy is really open, why rich countries subsidize crops in their land?

If the economy is really open, why workers cannot travel freely anywhere they could get a job and work honestly? Let me bring the quotation of the day on the NY Times of May 24, 2008:

"I don’t doubt for a moment that you are good, hard-working people who have done what you did to help your families. Unfortunately for you, you committed a violation of federal law."MARK W. BENNETT,a federal judge, to illegal immigrants sentenced to prison terms in Iowa."

If the economy is really open, why my human blood or other type of samples could not be used for a research project on MS in the USA? I quote from the email from the Multiple Sclerosis Genetic Group at University of California, San Francisco, as response when I volunteered for this project:

"We wanted to thank you for emailing the Multiple Sclerosis Genetic Susceptibility Project. Unfortunately, we cannot enroll your family at this time due to restrictions on transporting specimens outside of the 50 states. "

By the way, I live in Puerto Rico, a US territory for other purposes!

Could it be that the open market economy is just a pompous name for a convenient commercial exchange of goods?