Earlier quoted context omitted.
Why does there need to be a legitimate business purpose? What about freedom of speech? It's my website and I'll publish what I want to.
Eh, I think you got this backwards. If you really want to talk about this in terms of freedom of speech, LinkedIn is in the act of censoring? Edit: What I mean is that freedom of speech is not the same as freedom of censoring.
This is at least not quite true of First Amendment law. The concept of "compelled speech" exists in US law, and is considered an unconstitutional violation of the First Amendment. Exactly what falls into that category (and whether the right of domain owners to censor user-provided content as they see fit is protected), I'm not sure, but freedom of speech in the US certainly does at least sometimes include the right not to speak.