More to the point he was seeking right to assembly, it wasn't his speech that was suppressed. His views are well know, his sentiment registers broadly. He was denied assembly. Seems reasonable.
Your comment is confusing and vague. I assume you were talking about Milo Yiannopolis (sp?).
University of California (including the Berkeley site) is presumably public property. The 1st Amendment likely applies, at least as strongly there as elsewhere. If you are saying it "seems reasonable" for him being "denied assembly", is there any other public property where you WOULDN'T agree that it would be "reasonable" for him being "denied assembly"? I think it's long-established that government officials generally cannot deny people the right to speak on public property (at a time and in a manner that anyone else would be allowed to speak).
Somebody will probably argue that "public officials", per se, didn't attempt to obstruct Milo Y's right to be there, and speak. Well, no, the rioters did that. But I think that for the government to allow rioters to do things that would be illegal for government people to do, in itself would be a Constitutional problem. After all, the 14th Amendment guarantees "equal protection of the laws", and some of those laws deal with the right to "assemble" on "public property". Failure to use government police for to enforce Milo Y's right to assemble and speak would amount to a violation of his 14th Amendment rights.