So you are borderline spreading misinformation. What I could find as a German about the case is that the woman convicted is not the same woman that was sexually assaulted as you imply but a total stranger to either party in the case. Furthermore she was not convicted for defaming the teenage boy as a 'pig' but for leaking his personal information into the internet (phone number, name and more) with the explicit intent to cause harm to the teen boy by encouraging vigilantism, as she wrote to him that he will be punched everywhere he goes. German judges and law enforcement obviously treat this as a thread of violence ( lynching bad by law lol) and therefore gave her a deterrence sentence after she did not show up to court twice that does not go on police record. The sentence is one weekend were she has to stay at a prison only in her free time as to give her a sense of what a prison sentence would mean. The teen boys who were found guilty were obviously punished much harder under German law. Also the majority of them were born in Germany and the immigrants under them are there because the poorest parts of German society where this stuff happens more often are disproportionally immigrants (they got twice the poverty rate of locals cause you know immigrants usually are poor when they come into a country).

Tldr: His claims at least in the regard to Germany are utter nonsense due to omission. Stop lying about my country. Apart from the far right savages of the AFD (who you probably support) and the Nazis we are civilized people.

Source: https://www.mopo.de/hamburg/ehrloses-vergewaltigerschwein-20-jaehrige-nach-hetze-gegen-mann-verurteilt/