for those outside academia it may not seem such a big deal, but tenure is supposed to be inviolable. tenured professors have, for years, been able to talk about the inferiority of races and other things without getting fired.
of course, being against israel is a different thing. usually pro-palestine professors were dealt with at the tenure stage itself, by denying them promotion (for example, norm finkelstein and steve salaita). this method is newer and more audacious. the most likely outcome is a multi-million dollar settlement in her favour, but literally millions of dollars are less important to the university than maintaining the correct line on israel.