Because they're engaging in activity that also happens to be illegal - or punishable by law, in other words - and they'd rather the authorities remained unaware of their identities for fear of potential adverse repercussions in the future? Just a guess...
Funnily enough,
the most severe university campus attacks upon free speech rights in the contemporary US are against individuals and groups who are critical of Israeli policy in Palestine, but few conservatives have bothered to raise objections to such attacks on behalf of proponents of the Palestinian cause for some reason...
Anyhow, would this be regular-Fox-News-mouthpiece, frequent-speaker-at-conservative-conferences, Universal-Press-Syndicate-columnist and author-of-a-dozen-best-seller-books-printed-and-sold-by-major-publishers Ann Coulter that you're talking about? It's unfortunate that the event couldn't be accommodated over security fears (because the exchange of ideas and views is generally a healthy thing for any society), but let's not pretend Ann Coulter is a poor, voiceless soul on the powerless margins of US society here. She's also, irrespective of what she has claimed*, not actually entitled to the provision of a platform by anyone, never mind a university.
As far as I understand, it was
Coulter herself who cancelled her speech. The Berkeley College Republicans had
originally invited her to speak but had failed to consult with the university in respect of event security first. As a result, police were not able to offer advice on the most appropriate time and venue.
Alex Bollinger has
conveniently summarised the consequences of this (in a much more rigorous and circumspect summary than your dubious portrayal, I might add) for
LGBTQ Nation:
The university's
response is also worth re-posting here:
The free speech of privileged conservatives is dying a death, you say? I'm afraid I'm not convinced. What is it exactly that you feel Coulter is deprived from spouting in the public arena?
As an interesting aside, wasn't Coulter
recently condemning American footballer Colin Kaepernick for his conscientious refusal to stand for the US anthem (a means by which Kaepernick was exercising his right to free expression)? She went as far as calling for his suspension from the NFL and requested that he either like it or lump it. "I think it’s outrageous. He’s making a lot of money off this country. If he doesn’t like it I’m with Donald Trump, he can go to another country", said the outraged... erm, is "snowflake" the word I'm looking for here? ;) I guess Kaepernick just didn't share with her the "correct" sort of politics...
In fact, as you probably well know, many conservatives like the hypocritical Coulter will moan of "political correctness gone mad" when their bigotry and ignorance is scrutinised and challenged, but that phrase is really just a pitiful device utilised to try and discredit or police what is often-valid criticism (an exercising of free speech in itself) of their lazy, inaccurate and offensive opinions. So, not the greatest of free speech advocates after all then, is she? :rolleyes:
On the other hand, Noam Chomsky is always worth investing time in if you want to read or listen to a serious commentator of actual academic repute on matters relating to the protection and/or regulation of freedom of expression:
https://www.youtube.com/watch?v=VsdvYbG3U_U
*She deludedly claimed: "Even the most lefty, Coulter-hating judge would probably have had to order Berkeley to let me speak."