At the time of the edit, that post might have been in negative numbers. Voting expresses agreement, yes, but any score below 1 should be reserved for troll/frivolous/vulgar posts.
Precisely why I specified what "down-voting" is for. In my view, the correct score for a valid opinion that nobody else agrees with is 1. I feel up-voting can express both agreement and/or belief that something is valuable.
