1. People who have accounts on Facebook, Twitter and similar web services want to be public. There is no privacy on those sites. The Internet is a system where data packages (any statement) are sent around the world. The tight web that connects all Internet related computers makes them accessible to hackers.
And everybody should know that e-mails aren´t secret. In 2003 the U.S. Securities and Exchange Commission charged Henry Blodget, a former stock analyst at Merrill Lynch, with civil securities fraud (.wikipedia). The New York State Attorney General Eliot Spitzer had published Blodget`s private e-mails to friends where he had described stocks as garbage, stocks that he had recommended to buy as a Merrill Lynch analyst. Nobody is safe.
Publishing on social networks and expecting full privacy is like writing a letter with the line: "Hereby I am ignoring you" .
2. Government surveillance isn't new and isn't constrained to the Internet. There are already government agencies which don´t care much about privacy: The IRS and the tax authorities in other countries (in Germany "Finanzamt") have been sniffing in private matters, especially banking accounts, for a long time. There is not much that is private from the IRS. Do the Snowden backers criticize this privacy loss too?
For years crooks have been breaking into Swiss bank accounts and stealing private data from their customers. The German government (and the governments of federal German states) have been conspiring with the law breakers and thieves and have purchased that stolen data for millions of Euro (foxnews). Do Snowden backers complain about those invasions of privacy?
3. Last week Snowden got asylum in Russia and is backed by the Putin administration. He is now cooperating with a government which doesn`t care much about human rights or privacy and he prefers to live in a country where government opponents are easily thrown into prison.