Basically they have to decide if the risk outweighs the benefit of not encrypting such feeds.
Yeah it's scary knowing that insurgents used a $26 program to intercept signals from a $1 million dollar airplane. But do we risk an interception to potentially keep more of our soldiers safe?
As we know, we have better and faster mobility than the enemy does, however the enemy is more elusive simply because they lack the amount of technology that we do. We can't intercept enemy radio frequencies because they often use actual messengers to relay messages between two or more distant parties. It may take days for the message to travel from point A to point B.