Nothing on the linked page says anything about "Congress is exempt."

Everything I've read on the subject says exactly the opposite, that Congress and their staff are forced to purchase healthcare from the Healthcare Exchanges.

This pages says:

http://www.factcheck.org/2013/05/congress-and-an-exemption-f...

The law’s final language on this, written by Sen. Tom Coburn, says that: “the only health plans that the Federal Government may make available to Members of Congress and congressional staff with respect to their service as a Member of Congress or congressional staff shall be health plans that are — (I) created under this Act (or an amendment made by this Act); or (II) offered through an Exchange established under this Act.”