Boy, I really get tired of dealing with this one.
The First Amendment of the Constitution of the United States says:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Perhaps it is time to review this, since everyone seems to go around screaming that their "freedom of speech" is being violated these days. Note the highlighted word "Congress". The first amendment prevents the FEDERAL GOVERNMENT from abridging the freedom of speech. It doesn't prevent anyone else from abridging someone's freedom of speech--for example ME, restricting the comments made on my blog for any arbitrary reason I may decide.
Is this shocking? It shouldn't be. Since only government can truly silence freedom of speech. If your employer doesn't like what you're saying and fires you, you can still say what you want while unemployed--you have just suffered some consequences for your particular opinion (and yes, it is terribly unfair, but what can you do? Other people have freedom of speech, too and sometimes it trumps yours-- like when you are on their property). If I don't like what you say on my blog, I could delete your comments--but you could go somewhere else and make them.
So you see (and I have pointed this out before) there is a difference between being able to speak freely, and having to deal with the consequences of your speech. The limit of consequences is the First Amendment, which prevents the government from making your speech illegal, thus keeping you out of jail or suffering a worse fate at the hands of Big Brother.
Betsy's Page sums it up:
When will these people understand that the First Amendment concerns the government's restriction of someone's right to speak, not a university's decision to invite or not invite someone to speak at their campus, particularly when that speaker is under suspicion of fraud in his academic research.