The short answer is the "mindsets," as it always is. If it were not for the collective "mindsets" then, this would not/could not have happened... This is true re all the other tragedies of human history, past & present, and, unfortunately, seemingly for the foreseeable future. Alas, evolution is slow...
At first no one knew it was going on and later when they found out they didn't do anything because they didn't want to be involved.
This depends upon where you are; the laws/restrictions in countries affected by the Holocaust have stricter terms. Countries who were not involved like the USA or China have no restrictions.
The Nazi Party of Germany allowed the Holocaust to happen so the German people would be unified against the Jewish people.
The people weren't able to fight back since they didn't have enough power to overthrow the Nazis.
Nobody within the country had enough power to overthrow Hitler and the Nazis. It wasn't until other countries got involved in World War 2 when it was finally stopped.
The actions taken to bring about and to carry out the Holocaust were atrocious. These actions should have never been allowed.
Well the language would be scattered considering all the countries involved, but in terms of free speech, no one was allowed to talk; their machinery did all the talk for them.
No, it allowed Hitler to take over the government .
War.
Yes, but in time they had to surrender them.
generally they were allowed to wear their own clothes
During the Holocaust, they couldn't practice their faith without dying.