Right to free anonymous! speech is guaranteed in teh Constitution's First Amendment.
Right to privacy has been determined by the interpretation of the Constitution by the Supreme Court, and is often rooted in both the First and Fourth Amendments. Though not exclusively.
Doesn't matter. Some federal and state laws give citizens more rights, some less. They are both universally recognized rights at the federal level in the US.
It would be very helpful if we all recognized that these issues are important to some, even if they aren't to all. If the issue doesn't concern you at all, why start a flame war over it?