I'm part of the "disappointed but not surprised" group. Several (most) of my stories use UA characters, and to be honest, that's part of why I came here to begin with. This is (or was) pretty much the only forum I found that didn't already have prohibitions against UA story content. But I don't feel bitter about it. I feel like I was lucky to have the opportunity to explore that space while I did.
Some stories can be altered of course, the UA characters simply given a boost to 18 or a clever lack of specificity that allows the reader to imagine what they want. However this simply does not work in so many cases. When the character's behavior and experience level, speech and emotional maturity, let alone their physical description, is consistent with a much younger age than 18... well there's just no way around that.
I understand why most people despise such stories and the fear that allowing such forums to exist could foster real harm against real people. I may not agree with that, but I don't blame anyone for trying to stop what they see as a genuine threat to children. And I don't blame the service providers for not wanting to be seen as defending child abusers.
I guess the next question then is, do we need to remove our own existing UA content? Is this just for stories going forward?