One of the favorite cards pseudoscientists like to play is a comparison between themselves and a real scientist or innovator who was ridiculed, persecuted, or whatever. One well-known example of this is the Galileo Gambit. The same tactic is also used with Pasteur, Copernicus, the Wright Brothers, and pretty much everyone who overcame adversity and contributed something we now take for granted.
"But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown." -Carl SaganThe key problem with this argument is that the people being laughed at when this bit of Doggerel is brought up are typically woos: They've presented a hypothesis and don't have good evidence to back it up. Typically, their arguments consist of other forms of Doggerel intended to cover up their lack of evidence.
Ridicule, though often depicted as pointless, can serve a purpose: Humorous exaggeration and analogies, for example, often amplify a person's logical fallacies so that people can see them more easily. That's the purpose behind the Flying Spaghetti Monster: An exaggeration of Intelligent Design's single-minded pursuit of respect in the public relations front instead of scientific research. Unfortunately, the woos seldom respond to this exposure, often complaining that exposing their logical fallacies (which they don't admit to) is a form of persecution.
Sometimes, however, we aren't ridiculing them: Every once in a while, I post a problem with a woo hypothesis with a straight, text book-style response, and I'm still accused of ridicule.
I have a right to laugh when you look like you're doing something foolish. If you can show me that it actually works, I'll apologize. Until then, thank me for my negativity.