An aircraft avionics suite is not like anything most "hackers" are used to and they know it. The article does not raise any interesting points about aircraft network. It seemed to be another rubbish in-joke that backfired. Just like the musician who said he had a machine gun in his violin case.
Flight critical systems do not use Ethernet to transfer data.
Real time operating systems in general do not leave open "ports" vulnerable to attack. All dataflow is scheduled and known.
Access to Ethernet even beyond the firewall will only give access to non-critical data. So perhaps change a bit of weather data, corrupt a maintenance log, change incoming messages in general make a bit of a nuisance of themselves, but not take over the aircraft.