Well, because such questions are not:
about governments, policies and political processes within the scope defined in the help center
, where the referenced terms roughly split in three topics:
(1) policies introduced by governments;
(2) rules and processes by which policy is made in various legislatures or ruling bodies;
(3) supporters and opponents of legislation;
Normal human behavior, like expressing emotions, etiquette, shopping preferences, or private life simply do not qualify for "governments, policies and political processes".
Keep in mind that there are many objectively answerable questions, still off-topic here. For instance, "What is the politician X's favorite beer?" may be well answerable (by providing links to numerous interviews of X), but it is not about "governments and policies", hence off-topic here.
Questions on jokes may or may not be on-topic. If the background of joke reveals some objectively existing (again, remember the keyword?) "policy or political process", some may argue it is on-topic.
Personally, I don't like it for yet another reason: we are here to learn. I learned nothing by reading the referenced question and its answers, the name of Luxembourg in no way resembles me a kind of cheese, and I find poking on country's size is not a very bright idea, to say the least.