After 9/11 and the anthrax scare, the Postal Service and the Pentagon won't deliver letters addressed to "Any Wounded Soldier" because
- Terrorists could send toxic substances or demoralizing messages to American troops, without knowing specific soldiers
- Peace activists and other opponents of the war could send toxic substances or demoralizing messages to American troops, without knowing specific soldiers
There are folks who'd like to send 'good job / get well' messages to wounded soldiers whose names they don't know. This is a good thing, and I admire people who want to spread good cheer.
On the other hand, there's good reason to be careful. There are people out there with very sincerely-held beliefs who would find great satisfaction in sending a message like this to some GI who has lost friends overseas, and whose current assignment is a hospital bed:
"Thank God for IEDs
God Himself Has Now Become America's Terrorist, Killing
and Maiming American Troops in Strange Lands for Fag Sins."
(I'm not making up that quote.)
There may be a way to satisfy concerns about security and decency, and still get those "to any" messages through.
The "New York Times Regional Media Group Alabama" says that "Aides to Sen. Jeff Sessions, R-Ala., are offering to accept letters, screen them through the U.S. Capitol mail operation, and get them to members of the armed forces."
That sounds like a good idea. Senator Sessions' offices are set up to take email, snail mail, phone, and fax messages.
My guess is that other organizations have started matching "to any soldier" messages with specific American soldiers - or will start, now that the ban on "to any" messages is in the news again.
There's also a website, "To Our Soldiers" - I haven't researched it, but it looks like a they have a good idea.