It didn’t look to be a joke to Granny Clampett.
How was “hate-mail” defined, in this study?
Most likely most of them are something down the line of:
“We don’t like that you abuse your power, kill and slaughter people in Gaza.”
But since it comes from a German person, it’s straight away anti-Semitic, not every one is happy with the the Israeli do down there.
I was just in Savannah and Charleston and it seemed to be delivered in all seriousness - except by one tour guide, who admitted he was a transplanted Yankee and use the term with a definite twinkle. Also heard “The War Between the States” - never heard Civil War.
And they said it in serious contexts - like “during the War of Northern Aggression, this area was spared by the Union troops because they used the town to store arms.”
A lot of that article is really vague. The Guardian loves to disguise anecdotes as data.
The author of the article also did a pretty good job of skirting around the issue of who is responsible for the attacks, chants, etc. mentioned, and what their motives are.
Are you familiar with the term “pulling your leg”? 
If I saw a graffiti of a swastika close to an army base, my first thought would be: “Which ignorant soldier did this?”.
At the main airport in Taipei, Taiwan there are prayer rooms for Christians, Muslims and Buddhists… the later has a swastika
So, as a Brit, can I now claim that the US is a festering pit of anti-Semitism, as that study said you are worse than us?
In other news:
ZOMG Nazis in the US! Get out quick!
Exactly. That term isn’t used seriously by even the staunchest Civil War buffs. The War Between the States (often typed as “WBTS”) is the term they almost universally use. I’ve heard War for Southern Independence, but not in a long, long time. War of Northern Aggression is totally tongue in cheek.
Civil War buffs don’t use it, but Neo-Confederates (who know less about the CW than the average 5th grader) certainly use the term.
Its also problematic when someone uses a term developed by segregationists as a joke.
Some people way out in the fringe use it, naturally. I doubt they’re the ones leading tours in Charleston and Savannah.