@engineer,
I have always believed that
- Upthumbs should be used to reward well-thought out arguments whether I agree with them or not.
- Downthumbs should only be used for uncivil behavior. If I disagree with you, that doesn't warrant a downthumb. If you make a personal attack, then I am using the downthumb to disapprove of something that hurts any civil discussion.
I think maybe we should agree on what thumbs are for... so far you have suggested they are a mark of agreement/disagreement, or a popularity contest.
The way you are describing them allows the ideological majority here to put a big fat positive number on each others posts, and a negative number on anyone simply for disagreeing with them (whether the posts are well thought out or not).
To be honest, I think as Neptune suggested, the downthumbs are used as a big middle finger from the progressives on this site to everyone else.