Literally the only demand made by the dominion was they stop going through the wormhole and making incursions into.their sovereign space. The federation has a neutral zone with the romulans that has lasted like 100 years or more by that point, but if there’s a wormhole it’s somehow their god given right to poke around someone else’s territory? Not even to mention the Cardassian/Romulan pre emptive attack on the Founders homeworld. Prior to that they just sent spies and harrased ships in the gamma quadrant. Seems like a more than reasonable cause for war to me.
Starfleet probably shouldn’t have been so complacent beforehand anyway. They were getting pretty pompous prior
So you mean they should militarize harder in an off chance that an intervention of snarky and irresponsible being with godly power will bring them into the conflict with previously unknown and militarily vastly superior genocidal entity?