Maintain a civil tone. Finally, remember that the language you use reflects who you are. So even when you’re using strong language for strong purposes, keep it civil. People who call those who disagree with them names like wacko or fascist or pinto reveal themselves as extremists who have little interest it honest argument or productive discussion.
Their language works only with those who already agree with them. They’re contemptuous of anyone else. So if you want to be taken seriously, show respect for your readers even when you disagree with them. That’s the only way you’ll get them to consider your point of view.