Yes, I agree. On the other hand, there are parts of the law that protect people from offensive or potentially harmful speech acts, such as libel, sedition, or obscenity, and there are others.
What we have here is a speech act—well, calling the web “speech” is, I think, acceptable here—that issued a threat and also made other derogatory comments, as far as I can understand. The question is the threat. I have seen members threatened before. Often threats are figures of speech. One doesn't know what lies behind it, but at the minimum, it's an offensive thing to do.
The question before the committee is that if it goes beyond that, is it a breach? Clearly, in the doctrine of parliamentary privilege, threats of death against a member or any threats and efforts to intimidate a member in the performance of his or her duties are a breach of privilege.