[DanBC]

You can say them. You could chose not to say them for the same reason you chose not print anti-semitic cartoons or similar.

Freedom of speech is about governments restricting what citizens can say, and that hasn't happened here.

[raverbashing]

While the definition of freedom of speech is certainly government related, it is also influenced by external retaliation possibilities.

And in a modern society those retaliations should be strictly legal in nature (which unfortunately is often restrictive, but ok, it's part of the game)

Edit: wording

[kristofferR]

No, freedom of speech is about not restricting what people dare to say - it doesn't matter if it's the government or the terrorists that restrict it.