I have read on the net that authorities are having troubles monitoring Playstation 4 communications.
As usual the news are very non technical.
What makes the Playstation 4 network harder to intercept?
Many of the news were just sensational news, not actual. There have been reports surfacing after this that security agencies monitor xbox and playstation communications. It came up as a playstation was found in one of the Paris attackers flats. It was baseless and been debunked quickly (https://motherboard.vice.com/read/how-the-baseless-terrorists-communicating-over-playstation-4-rumor-got-started) however that didn't stop the hoax.
The communications also don't use crypto as opposed to many better communication techniques for secret communications.
So the answer is, its quite easy to intercept and Sony probably helps law-enforcement do it already. Some reports even say they are also using algorithms to search for suspicious activity themselves.
As the article does not go into detail, I am left to suspicion.
I suppose Sony does not use strong crypto; else, it would not be 'hard' but 'very hard' to get plain text. (cf. Apple ./. FBI)
There is however another aspect:
The network is huge, with a big number of active users, voice communication in masses amongst fellow gamers and vast possibilities to for example join a game session collectivly and use team voice communication to communicate.
It gets increasingly hard to find the needle in a haystack, the larger the haystack grows.
Note: This also assumes there is not already a warrant in place for a specific person, as the communication of a single person's account might very well be easily tracked by law enforcement with of without the help of Sony.