It is easier than that: in Germany for example swastikas are forbidden. But they don't prosecute or fine web pages served in other countries. Or books for that matter. In some countries communist symbology is prohibited, yet they don't fine US web pages for having them. And don't forget the Great Firewall: China blocks pages, and get along with some webs to tune what they serve. But you can publish Tiananmen massacre images in your european hosted web, and they don't fine you: it is their problem to limit access, and they understand it.
Just to clarify for casual readers: there’s no blanket ban on swastikas in Germany. You can use it for satire or historical reasons. You’re going to find a lot of swastikas on the German Wikipedia for example.
France stopped Yahoo! from selling nazi memorabilia in France (because it's illegal to do that in France). This actually went through the US courts and they agreed, mostly [0].
It's kinda voluntary, though, there's no international agreement about this.
This isn't strictly true, major magazines like Der Spiegel can use it for 'satire' or some such nonsense, it's basically at the whim of those in power as CJ Hopkins learned, his satirical use resulted in him being perversely punished, but state aligned magazines get a pass.
