That title is a bit misleading. They never leaked anything. This is an unfortunate side effect of military personnel voluntarily wearing a device that can track their movements. Strava was not given classified access to information. They aggregated data from all of their users and the military users just happened to…

Did you just say “unfortunately it poses no danger”? I consider that to be very fortunate and actually a result of the brilliant work of orbital mechanics scientists, so no fortune is involved at all.