This is an evolving situation which the White House is desperately trying to get their arms around control.   Currently the White House messaging to the U.S. media is an effort to sell the quarantine proposals as a U.S. Pentagon/Military decision/non-decision about quarantining soldiers who return from West Africa missions.  
However, it appears that specific angle’s narrative is driven as a needed cover story for DoD Secretary Hagel, and the Joint Chiefs – because  Italy, Spain and Germany  have told our military personnel (returning from Africa) they will face forced quarantine in their respective base countries.

WFB […] Major General Darryl A. Williams, who was appointed head of the U.S. command center in Liberia that coordinates the response to Ebola, was isolated along with several other Americans over the weekend, CNN reports.
The General’s “plane was met on the ground by Italian authorities ‘in full CDC gear,’” a U.S. official was quoted as telling CNN.
Williams and the others will now be monitored for 21 days at a U.S. military compound in Italy, according to the report.

The Italians forced U.S. Major General Williams into quarantine.

You can see the problem for the White House.  Our military forced to quarantine in other countries while President Obama is advocating exactly the opposite, and allowing everyone to come willy nilly in the U.S. 
To cover the dichotomy and try to avoid the conflict, the Joint Chief’s are debating a new rule forcing all of our military into quarantine.  This would change the dynamic to give the appearance of a decision made on our part and not forced by other nations, upon us.
However, such a rule might avoid the international optic but it would conflict with the White House.  How can the White House advocate for non-quarantine of West African healthcare workers, based on human rights violations, and yet force our military into the same quarantine.
(ABC NEWS) The Army has decided that troops returning from deployments to Liberia should be quarantined so they can be monitored for possible exposure to the Ebola virus and a general was among the first people affected.
The order immediately affected up to a dozen soldiers who returned to their home base in Italy this weekend, including Major General Darryl Williams, the former top U.S. commander in Liberia.
“Out of an abundance of caution the Army directed a small number of personnel, about a dozen, that recently returned to Italy to be monitored in a separate location at their home station of Vicenza,” Col. Steve Warren, a Pentagon spokesman, said today. “None of these individuals have shown any symptoms of exposure.”
Williams transferred command of Operation Unified Assistance on Saturday to Major General Gary Volesky, who commands the 101st Airborne Division. Williams and his staff returned to his command of U.S. Army Africa which is based in Vicenza, Italy. The order will also apply to several dozen more Army personnel returning to Vicenza later in the week.
Warren said that the decision was made by the Department of the Army and that Defense Secretary Chuck Hagel is aware of their decision.
There are 882 military personnel assigned to Operation Unified Assistance in Liberia and Senegal. They are being sent mainly to build Ebola treatment units and provide the infrastructure needed for additional treatment. They will not be providing health care to Ebola patients and will have minimal contacts with the general population.
Warren said there was no one incident that triggered the Army’s decision as the personnel in question did not have direct contact with Ebola patients. A Defense official said the Army made it’s decision over the weekend.
Ebola symptoms include fever, exhaustion, muscle ache, vomiting and diarrhea.
According to the DOD policy returning troops who have been exposed to the virus will be medically evacuated to the U.S. for treatment at Emory University Hospital in Atlanta or the National Institutes of Health Clinical Center in Bethesda, Maryland.  (link)