MarkK's comment about flying flags surprised me. So I did a little research. To a point he is correct, but its a bit more forgiving and does allow a few other flags. Cant see where it would be an issue on clothing by what I have read; "However, the law only refers to flags flown from flagpoles, not flags displayed in any other way...". I love one specific national exemption to the law. G-d Bless Them.
The permitted National flags that can be flown on a pole are: Ukraine, Greenland, The Faroe Islands, Sweden, Norway, Finland, Iceland and Germany; but not South Jutland or Texas. "The law also bans flags that are the equivalent of national flags, such as the Palestinian flag."
Organization flags like the EU and the UN and NATO are permitted as are corporate and Aggie flags. The ban is only on National flags.
https://lwid.dk/the-brief-story-of-legally-flying-national-flags-in-denmark/ is my only source and the internet can be amazingly unreliable so this might be no more correct than MarkK.
But thank you MarkK, I live and learn. One of the reasons I love the forum. Facinating.