What i see is a government on/off switch to isolate the US from the rest of the world in case of a mass cyber attack.

It is my understanding that Estonia is in the process of doing just that after Russian hackers did a cyber attack against them a few years ago.

But regarding the Internet controlling and the Cybersecurity Act of 2009...I do fear that our government is fishing for the opportunity to curb access via social networking sites like has been done in Iran and China.

Yeah its worked real good for Iran and China.
The Internet users in the rest of have helped to almost completely bypassed there censorship through proxies and other means.

The only thing China and Iran could do would be to shut down there Internet.
but that would stop there ability to use the Internet for spying /cyber attacks/ECT as they would not have the cover if there own population of Internet users/hacker to blame for any outside attacks.
If there Internet connection to the rest of the world was for the government only all other governments would know who was doing any attacks.