I think the key is that dotfiles are a different genre of (code) writing than production code, with different investment, different motivations, different pain points and histories, and a sensitivity to the author that's not required when analyzing production code. You're looking into someone's daily writings, not their polished releases.

I think the fear is scrutiny, rejection, mockery for something that clearly works for you and you don't ever expect anyone else to use. But also partly that it's exposure without much reward in return. All these feelings are normal and it's fine to share or not share them. Just please honour the authors of the dotfiles you read even if you wouldn't ever think to use code in the way they do!