I tend to down mod rude and aggressive people on here and I also up mod people who I think have been down modded unfairly.
I am not sure if I am alone with my way of thinking.
It only becomes abuse when people resort to karma bombing: downvoting a lot of comments by one user without reading them in order to subtract maximum karma. Fortunately we now have several levels of software to protect against that.
I guess we don't always behave in a grown up way online. I am as guilty of that as the next guy.
People often tell others acting like an ass to grow up.
This has nothing to do with being an informative description of children and more to do with PG's troll post, now that is somewhat ironic :p
For example, saying an asshole needs to grow up, is demeaning him by saying he is in an undesirable state (not grown up) which implies being a child is bad.