I have seen some people quote Thomas Jefferson as saying, "Ridicule is he only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them." I don't know whether he actually said that. Either way, I disagree with the proposition. A proposition must be intelligible before one can ridicule it. An "unintelligible proposition" would be one that one could not determine any meaning behind. And there would be no point to ridicule.
In actual usage, ridicule is used by people who don't want an idea considered, but are incapable of arguing against the idea. In essence, they find the idea challenges their indoctrination and they want it suppressed. For my part, I find those who use ridicule in place of argument to be useless to discussions. They contribute nothing.
UPDATE: Here is a site that brings my position into high relief. Interestingly, though it is not their intent, the people who use ridicule against christian ideas may as well be writing "Great post, Ray" to all of Ray Comfort's evolution posts. They are doing the same thing, even if they are not on the same side.