People, for good reason, have been building a Messiah-like image of Dany for a long time. The signs were always there that she was worse than we though, but many saw her as the heroine of this story. She wasn't, this is Jon's story at heart, but people aren't going to let that perception go easily. They needed to let people see she was changing but hold on to the hope that she was still their Messiah until the moment she wasn't. It would have been a bitter, harsh turn, but this abrupt makes people feel betrayed as viewers. That's unfortunate, they let something brilliant slip away.