Memes

Your first example is exactly what I wish we would collectively agree to avoid as a society. Recognizing when someone's trying to scam you (such as in a dishonest debate) needs to be taught in school starting young. When everyone has the skills necessary to recognize that Person A cannot be trusted, it becomes easy to solve the problem.

The times when you are ethically allowed to or even obliged to disregard someone's blatantly dishonest message can be taught to anyone if we all decide that is important enough. Freedom of speech is vulnerable to bad actors, and it's only the people who are willing to play fair who will suffer without better education and regulations put in place.