+/- is a good tool to express what you think of the posts made, I have no problems with it really. Also I look at it as the sign of the level of community involment, while I do not condone renown farming a cerain ammount of renown/infamy shows involement to some extent.
Don't mind getting + or - from anybody if that is their legitimate opinion of a post, it's quite silly some people feel really hurt by somebody - their posts so the go on a - spree. Nobody should get ofended really for a simple + or - on an online forum, it's nothing personal.
Allot of the opinions are not expressed properly by writing because not everybody is a english native speaker so it's quite easy to missinterprite the meaning and intention of some posts and I know in the past some of my posts have sturred up emotions while they were not mean to be malicious in any way (some were tho
)
Bottom line, you really souldn't pay too much attention to it and freely express your opinion regardless.