Germany's/Europe's past is not the US' past. What works for one country doesn't necessarily work for another.
The US is suffering from different problems and American Nazis are fuelled by different events, prominently the civil war and the US' complicated past with race. Having a nice Holocaust memorial isn't going to do much since most people don't make connections to their own heritage. It's not "their" past. A proper public discussion about the civil war would probably be a better fit.
But even then I have my doubts since the US as a whole isn't particularly great at atonement. That's more a cultural issue I fear. One of my favourite examples is the
Vietnam Veterans memorial in Washington. I didn't know about it until an American university professor brought it to my attention in a class about how countries deal with their dark past. He was extremely proud about the fact that such a huge memorial was build in such a prominent location and that they actually got a Vietnamese architect to design it. The memorial itself is basically a large black wall with the names of countless dead soldiers engraved in it. I'm sure many Americans would be just as proud about this as my teacher was, but many Germans and Europeans probably already see the problem.
I can guarantee you that, if this was a memorial in Germany (or in most other places in Europe), the names written on those walls would be of Vietnamese citizens who got killed during the war, and certainly NOT the names of soldiers who went there to do the killing.
This is the main difference in mindset and it's undoubtedly hard to overcome.
As I see it, Americans are too much in love with everything military related that they tend to look for stories of glory even in absolute atrocities. They'd rather have war heroes who just followed their orders, overcame the most difficult circumstances and did what they had to for the greater good than war criminals who murdered innocents and didn't even dare to question the orders they got.
There's a reason why war criminals in the US are glorified, why the confederacy is viewed in a positive light, why civil war re-enactment are always "heroic battles", why Custor's last stand is a legend and why so many Americans seem to have a hard on for the Wehrmacht.
And that's not going to chance with a few memorials, this needs deeper change in society first (and that's not going to happen)
