Yes because when people sign up for the military, it's their choice. Not other peoples'. When people sign up for the military, they are signing up to protect their country. But they know that they could still go over to other countries and fight for what's right. So yes. If people signed up for the military, they should be willing to over there without other people deciding when or why they should go over and help fight for what's right.
Syria's civil war is an internal struggle of the nation's residents against a despotic ruler. No one should get directly involved in Syria because the situation could quickly escalate to a regional conflict followed by World War III. The best policy is to leave well enough alone and offer humanitarian assistance rather than military aid.