If someone posts an idea that already is posted or posts in a really old thread and you think something is really wrong just use the report post button instead of attacking the user. If you think it is similar to another idea post a link to the thread in there and it can be merged together.
Too many people attacking users posting repeated ideas, but they also get attacked if they post in an older thread.
Disagreeing with others is also fine, but too many people turn their disagreements into attacks relating to a person being bad at the game, new, or other reasons. So be civil if you disagree. We try not to babysit the forums so don't make us have to otherwise it means longer time for patches to get done.