UND calls its teams the Sioux. It's the official name of the teams. The Sioux name wasn't given to UND's teams by the fans. Jews is not the official name of the Ajax team. It was a name unofficially adopted by the fans. Therefore, your first point isn't a similarity.
NDSU fans call themselves Bison, but they are not bison. Tampa Bay fans call themselves Buccaneers, but they are not buccaneers. Vikings fans call themselves Vikings, but they are not Vikings.
The only similarity is that you can make the same silly argument about any name of any sports team.
No argument here. And this is probably the only similarity you state with which I agree. In both cases, the answer advocated by you and some others is stop using a name so that racists and anti-Semites won't be overtly racist and anti-Semtic at sporting events -- as if it's perfectly fine for them to behave this way at any other time.
In other words, rather than backing those who are using a nickname in a positive, honorable fashion, you chose to punish them and reward the racists and and anti-Semites by forcing the team they hate to change its name.
You can force the fans of Ajax to stop calling their team the Jews, but the anti-Semitism will still be there. You can stop UND from using the Sioux name, but the racism will still be there. So what have you accomplished, other than caving into and encouraging racism and anti-Semitism?
How much do you need to understand about a bison (also the symbol of another culture) to be a Bison? How much do you need to understand about Vikings to be a Viking? Do you have to be wild to support the Minnesota Wild?
No they don't. The fans adopted the name on their own in defiance of anti-Semites who identified Amsterdam as a Jewish community.
Claim? Do you actually believe that UND adopted the name to insult the Sioux?
Nowhere in any of the stories you posted links to does it say that Ajax fans are acting with the intent to honor the Jews. That is simply your interpretation and it is wrong.
You're right. There are other more important things to worry about and things to work on that would actually make a difference if they were changed.