My understanding of that is basically this:

LaF signs FDP every set with EVO
Neither side ever help each other with suiciders or wars ever because they both netters and have history beef
LaF drops pact with EVO because "if LaF doesn't get to net, and won't get help, no one should net freely"...."we've protected the netters here alone far too long."....etc.(Y'alls words)
Elders/mercs decides to join with other tags planning to hit LaF after hearing word of that conversation and realizing their ally is getting pushed around
~War begins~
EVO accommodates LaF members who want to avoid war beginning in set 2
A lone wolf EVO member FA's various folks at war with LaF
LaF kills all EVO netters in response to the actions of 1 of their members but leaves alone the countries that were provided shelter by EVO
Various proxies go down cross server and are coupled with lots of derision, (ie, LaF members suiciding evo netters on team server, elders members hunting down RESIST on solos, etc)
War goes from relatively even numbers to a blowout

Annnnnnnnnd that's that for about half of our side, but I think the pact was dropped initially out of spite and in a hater-ish way. I get the sentiment but it's also not really fair to ask a 5 member netting tag to honor an FDP and have any real impact too. The pact seemed primarily dropped for historical reasons more than recency, but it absolutely was a domino in this war.