Being attacked with a knife means your life is being threatened and using a firearm would be legal even in Germany. The response has to be proportionate to the threat on life or limb not the size of the weapon.
Because when somebody attacks you with a knife, drawing a gun oftentimes will not even be an effective defense. But if that is all that's available to you, it's only reasonable to give it a try. You should shoot multiple times or empty the whole magazine though and yes, that's generally justified by the law if that's what it takes to stop the attack.
The exact thing has happened to police man and woman and yes, they get trained to shoot multiple times to defend themselves. Was an outcry in media a few times because people don't understand the situation those people were put into.
No, not even that, at least not in general. For example, it could be well within your rights to hit somebody who keeps insulting you.
And yes, not getting insulted is a protected right in Germany that you generally lawfully defendable under the "Notwehr" laws.
Wikipedia mentions more example of what you are generally allowed to protect:
> Das unberechtigte Anfertigen einer Fotoaufnahme stellt einen Angriff auf das Recht am eigenen Bild dar.[10] Das Anrauchen einer Person kann einen Angriff auf deren Ehre und Gesundheit darstellen.
Translation:
> Taking a photograph without authorization constitutes an infringement of the right to one's own image.[10] Exposed to secondhand smoke can constitute an infringement of a person's honor and health.
Will be easy enough to find more example if your are not satisfied with Wikipedia.
Neither of your sources supports "you may hit someone who keeps insulting you.". If you had linked the original sources, it would have been obvious that the examples are taken out of context.
> Bereits der Diebstahl mittelwertiger Gegenstände darf nach herrschender Meinung jedoch auch mit einer tödlichen Abwehrhandlung vereitelt werden, sollten mildere Mittel (wie Warnschüsse oder Schüsse auf die Beine) nicht zum Erfolg geführt haben bzw. nicht zur Verfügung stehen.[73][55][56]
> However, according to prevailing opinion, even the theft of items of moderate value may be thwarted by lethal self-defense if less severe measures (such as warning shots or shots aimed at the legs) have failed or are not available.[73][55][56]
More specifically, a teacher slapping a child to defend against six year old children: https://www.lawblog.de/archives/2016/09/08/richter-billigen-... https://famos.jura.uni-wuerzburg.de/wp-content/uploads/2017/...
He was also hit by the six year olds, but the court explicitly mentions the attack on his honor as well as foundation for their judgement.
Slapping the child was deemed to be the mildest mean for defence and therefore lawful.
Just to iterate on the first point, even theft of values starting as low as 100 Euro could justify lethal force. Knowing that honor is a protected right, it should not be surprising that hitting somebody can be justified when one get heavily and continuously insulted.
Your claims were that "not getting insulted is a protected right in Germany that you generally lawfully defendable under the "Notwehr" laws." and that "you may hit someone who keeps insulting you.".
Both are false.
More sources: > Mithin kann das Recht auf Notwehr grundsätzlich auch bei einer Beleidigung greifen und nicht etwa nur bei einer Körperverletzung oder Ähnlichem.
> Consequently, the right to self-defense can, in principle, also apply in the case of an insult, and not just in cases of bodily injury or similar offenses.
https://www.anwalt.org/notwehr/
Yes, the specific sentence you quoted was too hand waiving, not every insult can result in lawful self defence, but generally, defending against insults can be lawful.
Similarly, not everything somebody writes is protected by copyright, but generally what somebody writes can be protected by copyright.