Judge Margaret Ryan asked Fisher why the military doesn't take what she called a "commonsense" approach to disclosing routine court filings.
"Instead of making a constitutional issue out of it, why don't you just make it available?" she asked.
Appellants' attorney Shayana Kadidal said reporters' lack of access to written filings makes it hard for them to cover Manning's case, which is scheduled for trial in February.
"It's almost impossible to understand what's happening, even if you have access to the courtroom," he said.
The U.S. Supreme Court has held that the First Amendment mandates public access to criminal trials. The high court hasn't ruled that court records must be readily available but lower civilian court rulings favor that position.
Manning is charged with aiding the enemy, an offense punishable by life in prison, for allegedly sending hundreds of thousands of classified war logs and diplomatic cables to WikiLeaks while serving as an intelligence analyst in Iraq.
Audio of today's arguments: www.armfor.uscourts.gov