Now there's a sweeping generalisation if I ever saw one. In your own words you say "Why are you ALL mean". So yes you were saying they were all mean in the first.
Anyway, taking your additional comments at face value then you can't surmise the character of nearly 10 million people based on a couple of friends you have met (were they actually Swedish residents or Swedish diaspora as that makes a difference as well). As Greywolf rightly says, the language factor DOES play a big factor in perception as well. What you may perceive as being right in English they may understand as being wrong and hence there is room for a lot of misunderstanding.
If, as you say they left after finding out where you were from then actually you are doing the exact same thing as they did. Say for example you told them you were British and they cursed and walked away. That was due to either their experience with a small proportion of Brits who were rude, and/or stereotypes (and I'm a Brit hence using that as an example before anyone points fingers).
So what do you do? Turn around and tar Swedes with the same brush because of that small group of people. Secondly I don't get how they can be "friends" with you in the meaning of the word friend if they don't even know where you are from before walking away.
"Friends" don't make walk away on real friends for something like that. So something smells really wrong with what you are saying tbh. My experience of studying alongside Swedes (about 20-40) is that they are actually a great bunch of people.
Initially they may appear cool but this is usually whilst they work you out and vice versa. Once the initial shyness wears off then they were a cracking bunch of people with dry humour and great to spend time with. Yes there was the odd one which was caustic and rude..... but isn't that the case everywhere with every nationality?
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.