The military is slightly different than your job. We are often "at work" 24/7 in places far far from home. Contact with the "real world" is one of the things that keeps us sane.
Your job is different from my job in many respects. I and many others appreciate your service.
None of that changes the fact that your employer is still able to make policy on how the hardware it owns is used. More below.
Does your employer frequently take you to foreign countries for extended periods of time? Where there are no computers other than those owned by the company? Where there is no internet access other than what's provided by the company?
I didn't think so.
When someone is deployed to a combat zone (Iraq, Afghanistan) they should be able to keep in touch with their friends and family. It's a mental health issue. Twenty years ago soldiers/sailors/marines would write letters (delivered by the Post Office) and make an infrequent phonecall to their parents, spouse, or significant other. Those days are gone.
People now expect to be updated via blogs, social-networks, and to a lesser extent email. That's the world we live in and those expectations (social needs) don't go away just because someone's deployed.
I've been sent out of town for up to two weeks at a time for business, and my work computer still blocks Myspace and Facebook. Instead of going on about how it's my God-given right to use the company's computer however I damn well please to keep in touch with my family, I did things that were within the bounds of what my employer requires; I used email, instant messaging, my cell phone, and/or my own computer.
I wouldn't have any intention of forbidding deployed military personnel from keeping in contact with folks back home. I do, however, support their employer's right to maintain their own hardware and networks as they see fit. As far as I'm able to tell, the Marines' policy doesn't prohibit email, phone calls, texting, instant messaging, or other means of contact.
