Gerd You'd be surprised! Counseling or goading someone into ending their life is one such example. There are more, which mostly pertain to general public safety (You cannot yell 'Fire' in a crowded area without repercussions). There are also economic and social situations like False Advertising, Plagiarism, Inciting Violence/Riots . Words can definitely be a hammer, and there are several laws that exist which make them illegal in certain contexts.
With respect to this question and swearing - Racial and other slurs are the most notable and early exceptions to free speech - because it was deemed a reasonable expectation of human decency, and a necessity in some cases to protect minorities and other vulnerable groups.
However, today a lot of people are walking on eggshells about certain sensitive topics like gender identity, politics, obesity, and so on. I personally believe that these things should not get anyone prosecuted, and this is ultimately an ethical and moral issue, not a legal issue. So on this side of the issue, I fully agree with you that it is ultimately up to each person to fend for themselves, and solve these conflicts through gentle words, and not heated arguments. And certainly not legal prosecution! 🙂