So, now we know. Alice did try to tell the truth. However, as sages throughout history have learned, people prefer their own 'truths' to the facts. After a while, Alice just gave up and let people instead cling to the stories and 'truths' that gave them the most comfort and happiness. What harm did it do? What did it change?
Instead, she's simply tried to live her life and be a force of good whenever she could. I think that she's isolated by choice and intervenes only in limited ways and if it is clear it is necessary.
It's sad in a way; it must be a tremendously lonely and frustrating life to live.
[EDIT]
Further to that last point... Maybe I'm reading too much into it but Alice seems so distant in panel 4. In so many ways, she is the loneliest person on Earth. A living relic of a vanished epoch of human civilisation; born (or created) in a different time to a civilisation that barely even exists as a myth or legend anymore. Even its last physical relics long since gone to rust and dust. All that is left is her - a constant in a world changed beyond recognition.
No wonder she is so harsh and unsocial. Losing everything and everyone and then being condemned to live on in a world so different from the one in which she was born amongst people who can barely understand you and your nature must have worn at her sanity over the tens of centuries.
Thus is the fate of an immortal in the mortal world.