Well, Zora saw the future in which tragedies happened ( Antitise started the war, his remainers started the war after that ) so she killed him first and then she killed all his remainers too.
Mado didn't see that future but she saw the future that Zora killed Antitise for nothing and then start massacres.
Sum up, Zora saw the 1st future ( the future without interventions ) and Mado saw the 2nd future ( the future with Zora's interventions ).
That is why from Mado and others's pov Zora was a monster who killed people left and right but from Zora's pov she just wanted to prevent chaos before it happen ( she is quite radical though ).
With the calamity is the same, I think Zora's version is true because it is the original future without intervention. Mado can only see the future with Zora interventions so it is not really accurate anymore. Like how Mado would never see that Antitise would started a war in the future and just see Zora killed him first.
And if Zora is true about the calamity then Tokio should accept the mark to gain power to fight against the calamity in the future.