They can exist, but sound weird in the language.
is a total non-issue. You can't, in any country I'm aware of, choose absolutely any name you want.
Want a name that is offensive in your language? Your country probably won't let you do that, but some other one might, and yours still needs to accept that name as valid.
You can't just go to another country and change your name there, but if you have dual citizenship, you can usually change it in either one, and the other one needs to respect that.
For example, if you're male, and decide to change your name to Sarah, you totally can - but don't be surprised when people assume you're a woman.
And there are many countries, of which you are unaware, that do have pretty strict laws about what you are and aren't allowed to name your children. Iceland is the one that springs to mind off the top of my head. As I recall, Germany also has some limitations.
My point was governments do this all the time and it is a far cry from fascism. Elsewhere in the thread, it is mentioned that often times you have to compromise when registering a name in a different country (for instance, if the language does not contain a phoneme used in your name). In that case, you have to conform to the country's culture and language. Under that lens, banning names that violate cultural norms is not so crazy.
> You can't, in any country I'm aware of, choose absolutely any name you want.
Like in Germany can you name your kid "The Holocaust Didn't Happen"? No right?
Till the '90s at least there was an unofficial convention of anglicizing our surnames using the masculine form, ending up with things like Eleni (Helen) Papadopoulos, which in Greek sounds like a grammatical monstrosity.
Other surnames were commonly mangled in weird ways - Nicholas Metropolis (of the Metropolis-Hastings algorithm) surname was Μητρόπουλος (Mitropoulos). Metropolis is quite near phonetically but grammatically makes no sense in Greek.
Yes, people (specifically women) with strong opinion on the suffix of their name exist and proper solution of government is to butt off that decision. This is no the norm worth keeping by force.
Slovene, which has roughly the same gender and case as other Slavic languages manages to not have gendered surnames. So, e.g., Pirc Musar and her husband Aleš Musar have identical surnames. Czech, on the other hand, will cheerfully rename Hillary Clinton to Hillary Clintonová, applying their rules for gendered surnames to foreigners when writing in Czech.