Not necessarily true in this case but refusing to confirm or deny a loss is all part of operational security. The last thing you want to do is provide BDA to the enemy. Also if an attack was so successful that 30% of the force is 'wiped out' then that would be a clear signal for an attack where the odds on success have been dramatically improved.
Opsec has been the bane of modern media warfare. Can we cover up legitimately and repair a reverse before we read about it on CNN?