And I still would like to find out who and why down-voted Brian's statement.
It may have been accidental. I know I have cast 2 or 3 unintentional down votes in the time since I noticed we could vote on posts. 2 reasons- every other website I use that has a similar system, the "up" button is on the left (up and down, rather than down and up). I know at least once, I just pushed the wrong one. I probably would not have noticed, except that I was the first voter, and it lit up on my screen with a red "-1." I found I could fix it myself by upvoting twice (at least I think I fixed it).
And I know I had a second one, where the mouse just happened to be hovering over the arrows, and when I grabbed it, must have tapped hard enough for it to cast a vote.
Based on my own experience, it is possible that whoever punched the down arrow doesn't even know they did it.
Is up and down voting (as opposed to up only, or a "recommend this post" button) a function of the website software? Obviously it can be removed altogether (as on Crew Lounge), but is "up only" even an option?