Movies can be banned, but as far as i know, this is usually because the deem that illegal ideas and ideologies might be promoted, like with the Star Trek episode "Patterns of Force", in which the Nazi regime was described as "efficient".
http://en.memory-alpha.org/wiki/Patterns_of_Force_(episode)
But video games are the "root of all evil".
No one cares that millions play video games but have not harm any human or animal, but if a heavily mentally ill person harm a human or animal and that person had payed video games, everyone looses their mind...
The Swastika is indeed an ancient symbol that can be found all around the world. The great majority of Nazi/Fascist symbols are old symbols that where adopted, they did not invented them.
But, in some countries, and the number will increase, these symbols are illegal along with the ideologies, theories like Holocaust Denial, and any action to promote them. (Yes, the "Though Police" is already here.)
Even the Celtic Cross is illegal, which is a Celtic and later Christian Symbol...
The alternative would be that a separate forum would be created for the Germans, French, Austrians, etc, and IPs from these countries will be denied access to this forum. But this would require Admins who can speak these languages, and the players from these countries would not be able to voice their opinions and ideas equally.
Now, this forum is about video games. That means that you should not use it to voice your ideology, preach your faith or do anything other giving feedback about games, suggesting ideas, discussing modding, find support and everything else game related, so it is not a violation of Free Speech.
Basically things like the First Amendment from the Bill of Rights of the U.S Constitution, protect you
from the Government. You cannot visit someone's house, say something that offends him and then plead the First.
Although this will cause inconvenience in the discussions about WWII video games, and this should be the main concern.
(Personally i favor censored versions of video games, like Iron Cross flag instead of Swastika flag, for countries where these symbols are illegal, and a version with the actual real symbols for the countries that have no law against them.)