If you’re up to the challenge of advocating and striving to educate everyone you encounter who is close-minded/ignorant, I think that’s incredibly admirable.
Moving forward with that plan, I would encourage you to remember two things:
Some people are bigoted, obstinate, and/or completely egocentric. No matter what you do, they will not relinquish their hatred, so recognize when a mind can’t be changed, and pick your battles.
If you find that contending with such confrontations is too exhausting (as many do) you can always fall back on an “official” vest (I believe sellers on Etsy can make custom ones based on your dog’s measurements). You could even wear the crocheted one on certain occasions, and switch when the situation called for it. If you want to advocate but feel like it’s draining your very soul, sometimes people give out cards/pamphlets that cover the basics when they don’t have the time/energy to do so themselves. Some people make these, but I believe they can be purchased as well.
To see a rough example of what that might look like, check out this infographic from Carma Poodale, or this brochure, any of these cards located on Amazon although personally I like this one best since it takes the extra step of noting that SD handlers don’t have to provide a card, thus protecting teams who come along after you. There’s a few different printable resources here for more specific scenarios. As a disclaimer, I have not vetted all of these websites, I’ve simply bookmarked them over time as a jumping off point. Hopefully you’ll find them helpful.