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.
Decided to post about this in stsr trek reddit. Apparently destroying New Bajor, a colony in Dominiom space, without sending a diplomat first made it the fault of The Dominion. I'm pretty sure the onus of diplomacy is on the people who want to establish a colonial presence in your sovereign territory and not.the other way around. Like, if China decided Wyoming was there's and just brought dudes in, the expectation wouldn't be to send a diplomatic envoy.
The racism showed up fast
Dude is acting under the presumption that colonists have rights in the place they're invading