When the government does not allow its population to freely speak against it, it's just waiting to be abused by one bad leader.
You're not allowed to insult anyone, https://www.gesetze-im-internet.de/stgb/__185.html , though the term "insult" is not nearly as broadly defined as in everyday speech. The law dates back to the 18th century, and has largely been unchanged for 150 years. I really don't understand the recent outrage over these and other laws. We have been fine.
More background: https://de.wikipedia.org/wiki/Beleidigung_(Deutschland)
The last 150 years of Germany have...ahem...not been what I would call "fine."
It would be interesting to have a replay of history without this law and similar ones related to it. Could be nothing different happens.
On the other hand, any law regulating speech is going to have a reverberating effect on the marketplace of ideas with 2nd and 3rd order outcomes that are impossible to disentangle after the fact.
But it's certainly not been because of that law…
At the very least I'm sure you'll agree we've been fine the last 80 or so years. Again, I'm just saying I don't understand the outrage right now.
However, I don't see how this would imply the law that's been in place for 150 years would suddenly be bad. In fact, one might argue that precisely because so much communication is happening in public now, more regulation is needed.
Germany restricts insulting individuals / your neighbour, police officer, a pastor or a minister. There’s no special law for politicians. Political criticism is protected under the Basic Law (constitution). Go ahead and be crucial about a politician’s actions but don’t insult their person’s honour or use a slur. That’s not your freedom of speech, that’s the dignity. In fact, you can even insult the government! You can say German government as the government is not a person.
Anyone can defame anyone else on the US. The only time the libel or slander laws apply is when the defamed person can prove real harm in court. Not harm to dignity, but monetary loss, personal loss, or physical injury. These are very high bars to clear.
If people could sue and win just for proving willful or negligent defamation of character, a lot of extremist influencers would be in the poor house.