It's because the Ascians were tempered by Zodiark. Emet-Selch admits to as much in Shadowbringers. And if you've played all of FFXIV current story you know that once a primal tempers you your choice of free will is gone. Your devoted heart and soul to the primal who tempered you. And Zodiark didn't want to talk to Hydaelin he wanted more Aether and more followers to grow stronger and sustain himself. So those he tempered of course won't go to Hydaelin for a tea party to discuss the RIGHT way to save the world. Ultimately the Aumarotians chose to sacrifice people they deemed 'lesser' than themselves in order to sustain themselves and their 'paradise' forsaking the need to better the Star and instead better themselves. Hydaelin was disgusted by their nihilistic vain glory and sundered Etheirys for the sake of addressing the problems she was dealing with. And as that cutscene shows she regretted it had come to that but stood firm in her decision and walked along with all the suffering and suffering herself in the process. I don't understand why everyone is harping on Hydaelin and defending the Aumarotians though. The Aumarotians wanted to sacrifice others for themselves while Hydaelin sacrificed herself for others. It's eerily similar to todays world where doing the right thing is 'virtue signaling' and doing the wrong thing is 'freedom'. Shake my head.