I have found that it’s best to put all the negativity and the myths out in the open early on during a presentation. When I speak to a group of potential speakers, I know they’re thinking “I’m never going to be comfortable speaking in front of strangers.”
I’ll say something like “I know speaking is the number one fear according to the Book of Lists, and dying is fifth. With that as a given, then most people would rather be in the box than giving the eulogy.”
It usually gets a laugh and it brings the fact out into the open. Then I talk about my early experiences with speaking, which weren’t pretty. I get the audience to relax by relating to their personal experiences.
If there is an obvious belief system that is contrary to supporting your concepts, address it head on. But avoid be confrontational or argumentative at all costs.