If you ever posted a sickle-and-hammer to the web, visible to the Hungarian public -- distributing it -- then you possibly could be fined for it. If you visit Hungary and you got fined, would you consider it just? Here's the Hungarian Criminal Code article in question:
Article 335(1). Any person who
a) distributes;
b) uses in public;
c) exhibits in public;
a swastika, the SS sign, an arrow-cross, a hammer and sickle, a five-pointed red star or a symbol
depicting the above, – unless a graver crime is realised – commits a misdemeanour, and shall be liable to
punishment with a fine.
(2) The person who uses a symbol of despotism for the purposes of the dissemination of knowledge,
education, science, or art, or with the purpose of information about the events of history or the present
time shall not be punishable.
(3) The provisions of subsections (1) and (2) do not extend to the official symbols of states in force.
As I've already noted, Germany and other countries have enforced their no-Nazi-stuff laws against US-based entities.
If you do a thing that's illegal in Hungary, and then put yourself on Hungarian soil, I'm not going to be surprised when you get arrested. In other words, this is not the knock-down "that'll really show him!" counterexample you're looking for.
This seems untenable. Now, to travel to another country for holiday, I need to look back on everything I've ever done, (even something so minute as distribute an image of a hammer and sickle) and pore over the laws of that country and determine I have not ever been in violation of _any_ of them?
I don't think most people would say that's how it should be, it's just the way it currently is. Law enforcement typically does not care about your convenience.
Article 335(1). Any person who a) distributes; b) uses in public; c) exhibits in public; a swastika, the SS sign, an arrow-cross, a hammer and sickle, a five-pointed red star or a symbol depicting the above, – unless a graver crime is realised – commits a misdemeanour, and shall be liable to punishment with a fine. (2) The person who uses a symbol of despotism for the purposes of the dissemination of knowledge, education, science, or art, or with the purpose of information about the events of history or the present time shall not be punishable. (3) The provisions of subsections (1) and (2) do not extend to the official symbols of states in force.