In this specific case she was a guest of Essex University and not a tenured professor there, so they were under no specific obligation to provide a platform for her.

    Jo Phoenix, a professor of criminology 
    at Britain’s Open University, was due to 
    give a talk at Essex University

To your point though, I wouldn't find it good for a tenured professor to lose their job for such a thing. However, even the idea of tenure really is meant to be more like "freedom from interference" and not "unlimited freedom without consequences", right? And of course the tenure track prior to tenure is of course a period of intense vetting.