No she didn't cancel.  The group that invited her failed to jump through the proper hoops and application processes, and Berkeley cancelled on Coulter.  One of the reasons for those application processes is to ensure proper security because of past violence due to students who were being knobs and became violent.  I (maybe liberally) connected the dots to students who have created an atmosphere of fear by introducing violence whenever someone says something with which they disagree, and hence are blocking free speech by introducing this atmosphere of fear.  It's not much short of sloppy totalitarianism.

The regulations shouldn't be necessary, she should be able to show up and speak without fear of anyone being hurt.  But we have some babies that are eroding the right to free speech.