The subspace anomaly caused everyone to obey the rules of a quantum reality in which people followed the tropes of 20th century American musicals. It was observed on numerous occasions that people affected by this phenomenon would generally sing their true feelings to those around them.
Considering this, we can contemplate that high ranking members of the Klingon Imperial Fleet were more open to regular relations with Starfleet and the greater galactic society than previously assumed.
The captain of this cruiser laments that his only interaction with the Federation comes during times of conflict. As shown by Lieutenant Spock after the events of this subspace rift and the hostilities on Cajitar IV, complex diplomatic situations can be defused by respect for and participation in Klingon social activities.
Knowing this, we can assume that significant damage was done by the widespread adoption of the “Vulcan Hello” by one of the founding members of the Federation. Had the Vulcans been more forthcoming about the history of this first-strike doctrine, the Federation may have been able to avoid earlier conflicts with the Klingons by reaching out proactively to their neighbors and not only call them when they’ve got dramas.