That's the point--from the audience's point-of-view, she didn't "call out sick;" she didn't show. And she did that much of this short run. Perhaps live theatre isn't a great fit for this actress, particularly if she does have an anxiety disorder. She can certainly continue to earn millions in TV and movies without having to face a live audience.
As for not getting vitriol that people post about actors being out-- the audience has been promised a certain actor and that promise is splashed on ad after ad and article after article. The audience lays out lots of money to see her, not particularly the show she's in.
How do you expect people to react when the actor doesn't show and gives no reason for the absence? Sure, actors are human, but so are audience members.