Dealing with diabetes on a daily basis can be it's own challenge, but correcting and educating the public is another challenge entirely. Here's the thing: it's necessary that you manage diabetes, and your choice as to how you decide to educate and advocate.
Our poll results showed that the Children with Diabetes community overwhelming supports the "correct their misconception gently but firmly" option, which is a great way to bring education to diabetes newbies and stigma-perpetuators alike.
Sometimes it's useful to point folks with questions and concerns to a trusted website (like Children with Diabetes), or other sites that share diabetes-related science, studies, and high-quality research. For assistance on managing the emotional side of diabetes, the Behavioral Diabetes Institute has an excellent slate of resources, including their Diabetes Etiquette cards (view the PDF) and several educational (and inspirational!) videos.