Unfortunatly, there are still widespread and negative cultural biases, stereotypes, and antiquated beliefs that are held by society against snakes, and reptiles in general; beliefs that they are slimy, disguisting, or dangerous. There is not one single reptile keeper or enthusiast I know of who has not experienced this.
As others here have already stated, much of it stems from ignorance and lack of awareness, education, and understanding of things people fear or do not understand. You should use your and your son's newfound interest in these wonderful and truly misunderstood animals to educate the public about them whenever possible. If there is a herpetological society in your area, I would highly recommend joining one. There you can share your interest and passion for these animals with other like minded individuals, and be actively involved in educating the community about reptiles and amphibians. I have been long involved with the Madison area Herpetological Society, and have met many great people, many of whom are now some of my best friends.
Seeing that you are in MN, it might be of interest to you to check out the Minnesota Herpetological Society. Obviously, you won't be able to get through to everyone with these endeavors, but I think you will see that once you join one, reception towards our cause will be overwhelmingly positve. It seems to have been for us, MAHS. Good luck!
http://www.mnherpsoc.com/