I guess you didn't actually say "vaccines cause autism". You merely spoke about the stories you hear about vaccines in the autism community, and suggested that

I guess you didn't actually say "vaccines cause autism". You merely spoke about the stories you hear about vaccines in the autism community, and suggested that everyone else would change their mind if only they had the same experience -- without any clarification as to what you actually meant that is different from the usual "vaccines cause autism" tripe. Do not blame others for misunderstanding when you communicate badly (see also http://xkcd.com/169/ http://xkcd.com/169/ ). If you want to have a "constructive conversation", start by communicating better. Explain what you mean, instead of getting angry at people for not guessing what you mean.