Someone like Russia or China who has a spy satellite is not the likely threat to US forces in Afghanistan. The threat is from guerrillas and the like who may have access to the Internet.
Clearly, the military needs to give much stronger guidance about uploading GPS location data even if it's anonymized before being made public. There are also likely civilian contractors or others who may just be ignorant about the implications of their actions. Facebook, social media, and the worldwide availability of the Internet are already a huge source of leaks.
During WWII, the Chicago Tribune published a story giving away the fact that the US had broken Japanese codes leading up to the Battle of Midway. It was a huge security breach. However, since the Japanese had no access to the Chicago Tribune, they never read the article and never knew their codes had been broken. Security through obscurity no longer works.