All comments on Topix are covered under the First Amendment.
You have to lose your job or business to get a case against multiple posters on Topix.
And you have to prove all statements are false.
False---I suggest you pick up the nearest legal text and familiarize yourself with the concepts of "per se" libel and slander.
Proof of damages does not have to exist in certain per se cases.
For example, If I was in public and said "doctor X amputated the wrong leg yesterday on person Y", the doctor can successfully sue for punitive and compensatory damages....and win.
Feel free to educate yourself before spreading stupidity.