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.
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.