MitM'ing the traffic using a trusted root CA allows TLS traffic to be decrypted, even if perfect forward secrecy is used. That's what we did to produce the decrypted PCAP shown in the Wireshark screenshot.
If you use an HTTP proxy or terminate the TLS connection in some other way, yes. I was thinking of the situation where you use Wireshark directly on one of the endpoints, i.e. a passive MitM attack.