You're correct, there are ways to reach undecided or "Obama '12 to tRump '16" voters, but I suspect Mr. Rhein is already doing that, even beyond his efforts on Medium. (Personally, I'm hand writing a message and the addresses on postcards for 400 swing voters in important states, as well as contributing what money I'm able.)

But this is about defending one's own "castle", and regaining some amount of personal control for the safety of someone's family when there is a clear threat of madness in the immediate area, posing an immediate risk. A way of saying, "I respect your freedom, but I am not turning my back on the great harm your candidate has caused." (And nothing I see would bring harm on Mr. Rhein's family or home.)

Respectfully.