Hermits and Cranks: Lessons from Martin Gardner on Recognizing Pseudoscientists
scientificamerican.com
scientificamerican.com
It occurs to me that a skeptic should not predicate his skepticism on someone's background or how "crazy" they are. A skeptic ought to thoroughly consider something solely on its merits.
Consider, for a moment, that instead of saying that cranks are usually antisocial we said that cranks are usually black. Supposing that is true, would it be fair to say we should be more skeptical of black scientists? Of course not.
This is just prejudiced trash.
There's examples of scientists who worked alone and were rejected by "the establishment". Darwin and Galileo are the classic examples. Though, their persecution had an obvious root.
Counter examples would include Newton, Einstein, Faraday, and above all Cavendish. Complete outsiders who had a big impact and were highly respected by their peers.
In some less scientific fields, though, it seems that the cranks have the upper hand.
You have answered your own question, in a way; they gained the respect of their peers. This was achieved through the quality of their work which provided better explanations of experiments and predictions which others could verify.
I said the others were "counter examples" - outsiders who were accepted, probably due to the fact that their ideas only challenged science.
Also, Cavendish was quite well accepted by the Royal Society. They probably found him a little quiet though, and he would have had to leave the room if a female maid brought in any drinks ... but he was accepted.