All internet forums are not immune from those on the end of the spectrum who just can't control their emotions and resort to unsavoury methods to make their point.
We had an incredible one on our local community page on FB. Essentially, someone wanted to restrict the major road between his house and his workplace to bicycles only without any consideration to other residents that live on this road. His one-man campaign was incredible, threatening legal action when challenged, and even scared council enough to conduct a study. He's still at it years later.