>Is it true that walking on rural roads at night is horrendously dangerous?

No. It's not. You just can't expect drivers to see you so you have to take care and step more or less off the road if there isn't a wide shoulder available for your use at that spot. It's not a big deal because cars aren't that frequent.

It's really no different than any industrial workplace where it is expected that the lighter traffic will make way for the heavier traffic.