Rebuttal is a supposedly reasoned opposition to someone's assertion. Ridicule is not acceptable in argument any more than insult is.

If I state flatly that I think everyone should be required to carry a handgun, that is my opinion. If I present a reasoned argument to support this opinion you are welcome to dissent and express your opinion. You are not free to insult or ridicule me. Nor are you free to state that I believe that everyone should be required to carry a handgun, as an "If" statement in this context is exemplary. (I believe everyone should carry a sawed-off shotgun.)