Reddit tried to sticky this post for moderators around 12p CST today, and they've since tried to bury it. Thought it might be good to back up the link here.
Actually not always. I remember the good ol' days of early Reddit where you could have astronomically negative votes on posts. Back in the simpler times when r/f7u12 and rAdviceAnimals ruled. It was only a feel years ago when they changed how upvotes and downvotes worked
Back in my day, they did have negative values. I want to say the EA Star Wars Battlefront fiasco was about the time they switched to hiding how very hated a post/comment is.
They used to not even be combined. You had separate up and down vote counters. The they combined them, and you could go negative and even get a cross it it was controversial.