Why have red votes? Simply to extend the range of opinion beyond just "positive" and "neutral," and give people a chance to register a negative reaction.
Why have red votes? Because some people are innocently unaware that they are off-topic, spreading rumors, unfocused, etc. until given feedback. These people are not bashers, or pumpers for other stocks, they are just not thinking of others. They may not even know what the "OT" (Off Topic) system is, or when it applies to their own post.
Why have red votes? We still have occasional bashers, pumpers, rumor-spreaders etc who intentionally post on this site. Multiple red votes highlight these posts.
As I said before, the red/green voting system works best when more votes are cast both positive and negative. Exercise your right to vote.