There will always be these cases. However, unless you've never shied away from something, can you blame someone for not liking a snake?
Sure it's rude, but it happens, the best we can do is calmly explain that their actions have no factual basis.
Now if they're so afraid they won't enter your house, maybe they're not even worth acknowledging.
I'm terrified of spiders, and not a fan of scorpions...if I didn't have patient people to teach me more I'd still be the same way.