"Cyber" is a very frequently misused buzzword people like to throw around because it sounds futuristic and cool. What many people mean when they use the word is "computer-related".
What it actually means is the short form of Cybernetic: The integration of human and technology.
What the quote could mean (you are not providing context) is that machine learning can help for security problems in machine-machine interaction (digital) but not human-machine interaction (cybernetic). For example, you can already use machine learning to teach a program to automatically detect an automated brute force attack on a login form, but you can't yet teach it to automatically detect a phishing attempt. (I am not claiming this is right or wrong, just that it might be what the author wants to say)
Its as brief as that.
– Makan Jul 18 '16 at 14:01