You seem to be ignoring the context of the Sirian Houses having 800 years of peaceful - with the minor exemption of Rheinland waging war on a Kusari corporation - coexistence and Gallia being the big bad for virtually its entire existence. It has now welcomed the Enclave back into its militaristic dictatorship regime.
You linked story material from the period Gallia was under different leadership.
I will also remark that certain story elements were clearly rushed at the end of the Gallic war. Again, we're dealing with a setting of Houses that fled the Sol system because of war, vowing to never let such atrocities happen again. Relations with a warmongering, genocidal House would not warm up very quickly.
On the subject of things that were rushed: the Gallic Reunification unfortunately was not well-coordinated between the Developer and Admin teams at the time, leading to many last-minute changes. In hindsight, it would have been good to shift Gallic-Sirian rephacks back to nodock, but this was clearly overlooked.