There are effective rules about speeches by military personnel. You basically clear everything ahead of time. If you screw up....you get reprimanded or kicked out. Its simple. I doubt that the General ever read the rules or ever cared for them. The problem is that you could have some military general with the exact opposite type speech...and we'd have to take action against him....so I think this dude ought to take whatever evenhanded punishment that they dish out. He earned it one way or another.
While we need to follow the rules, it should be tempered with good sense. Talking with God's people about Him and the United States does not offend me. Neither would a musilm in uniform offend me if he preached support for his god and SUPPORT of the United States in his mosque.