How are prisons and the military so different when it comes to free speech and expression?

There is limited free speech for military and according to first amendment there is free speech for the prisoners.

Explanation:

According to the first and fourteenth amendments of the US constitution it allows the citizens to express their opinion and ideas only up to a level or limitations. According to the amendments the prison and military is also adhered to free speech and expression.

The Supreme Court in its ruling as stated that prisoner can have contact with the outside world subjected to adhere to the internal security. It says that they can send and receive mails and have outside contact according the first Amendment.

But in military free speech is very limited and it has regulation under include the Uniform Code of Military Justice (UCMJ) and Defence Department Directives

constructive criticism