Here's a treatise that explains a lot of the debating styles agoin' on on FR.
http://www.lawfulpath.com/ref/brainwsh.shtml
There is no rhetorical or debating rule concerning responses to arguments with no merit. In other words, nothing requires that absurdities be treated as "valid" arguments.
Furthermore, while we are on the subject of debating technique . . . one should not expect to be taken seriously in a universal sense if one presumes to make absurd, throw-away comments such as the one above. In summation, if one expects to be treated with respect, then one should make comments worthy of respect.