Illegal means “violating the law.” Germany as a nation passed a law to exterminate Jews, so no national laws were violated. Thus, Hitler’s act is NOT illegal.
Hitler as the Commander-in-Chief of Germany as a nation issued orders based on German law to protect the German people from the National Security Threat (NST) that Jews in Germany posed.
When a nation degenerates in terms of morality, that creates a serious National Security Threat (NST), because immorality fuels crimes, such as sexual crimes.
In Germany, Jews played a major leadership role in expanding homosexuality (a heinous crime according to the Holy Bible) in Germany.
Sexual crimes do not proliferate in a vacuum. There has to be a socio-political environment that encourages sexual immorality for proliferation of sexual crimes.
When Jews push gay marriage and homosexuality (serious crimes according to the Holy Bible) and create a socio-political environment “friendly” to homosexuality (which is an evil crime according to the Holy Bible), Jews create a socio-political envirnoment “friendly” to sexual crimes.
As sexual crimes proliferate, the nation reaches critical mass of chaos and lawlessness, and that is what Germany was facing, thanks to the aggressive immorality push by Jews of Germany to proliferate homosexuality in Germany. Thus, Jews in Germany became a National Security Threat (NST) to all German citizens who wanted to live in peace and order.
God the Father gave laws in the Holy Bible, so that people can enjoy peace, order, and prosperity.
When these Bible Laws are attacked, as the Jews did in Germany and do in America, serious National Security Threat (NST) arises, because society degenerates into moral dissolution and chaos.
Immorality destroys nations, as can be cleary seen in other democracies, such as Greece democracy and Rome democracy.
German democracy sought to save itself from the National Security Threat (NST), and that is why the nation of Germany under the leadership of Hitler passed laws to protect Germany and the good citizens of Germany.
Germany determined that this was the best course of action to counter the National Security Threat (NST) after years of tolerance of homosexuality in the country (fueled by Jewish power, wealth, intellectuals, and lobbying) posed serious national threat to the nation and its citizens.
Hitler as the Commander-in-Chief of Germany tried to protect Germany as a nation and good German citizens by legally carrying out the arrest and execution of German Jews.
What Hitler did was completely legal in Germany, so Hitler did not commit any illegal acts when carrying out the Final Solution of Jews in Germany.