We should never forget and should remain as objective as possible when looking at the history, but people that proudly wear these symbols while parading on the streets don't have the first clue what they actually stand for.

They do know WWII is one of the most disgusting and saddest things humanity has every experienced, right?

It depends...

guys I know here some rough German and do a Nazi salute...

Mocking Nazis or imitating them seems to a thing these days.

I have nothing against dressing up as Nazis but it gets weird when it's meant to celebrate something.

Thats weird.

the kids said they wanted to go as stormtroopers, but the person organizing the event never saw star wars...

I found Hitlers 'Mein Kampf' in the fantasy section of a Mumbai bookstore, right next to LotR. I admit, that was pretty funny.

That tank though!
A+++

Is there context as to why they chose Nazi's?

I guess SS Uniforms look cool, they are made by Hugo Boss afterall. And some even have this metal skull on their hats. And the Swastika is striking.

I understand that it has a certain appeal if you do not consider the atrocities commited.