1: Polar had stated several times we did not consider the war over, it is your gov that continued to ghost her despite being very active in other FA efforts that led to this. TEst was not in any way at peace with us and that had been made clear multiple times.
2: We wanted surrenders and guarantees that they would not immediately use their infra in the middle of a war time to start funding their allies. Given the character of those involved having a protector guarantee that alliances they protect abide by a peace agreement is not unreasonable. Negotiation is in bad faith when your leader ignores our representative for considerable lengths of time, and deemed it necessary to return to open combat.
3: T$ escalated this by aggressively attacking BK who was continuing hostilities in the current war. As for coalitions, T$ also called Sans and Typhon before BK called any allies of their own, indicating that you were escalating to full coalition warfare in aid of the enemy side.