I'd like to address your specific title question, rather than the "too broad" issue
Our Help Center states:
To prevent your question from being flagged and possibly removed, avoid asking subjective questions where …
- every answer is equally valid,
- your answer is provided along with the question, and you expect more answers,
- there is no actual problem to be solved,
- you are asking an open-ended, hypothetical question,
- your question is just a rant in disguise.
For the sake of completeness, let me explain all five points.
When you ask a fishing-for-ideas question (aka brainstorming, idea-generation, or an infinite list of things), you are asking a question where all answers are equally valid. This breaks Stack Exchange's Q&A model (one-specific-question/one-best-answer, SE is not a discussion forum). Stack Exchange owns the stacks, and while individual stacks enjoy considerable latitude concerning how to deal with many specific rules and the culture of the stack, it's still Stack Exchange's stack — and they have rules we are expected to observe. Insofar as it is humanly possible for questions concerning the creative and imaginative act of world building, questions are expected to be objective and scoped such that a best answer can be selected. Our take on this is that questions must seek a finite list of things. Questions asked such that every answer is equally valid are often closed as "primarily opinion-based."
If you already have an answer, why are you asking the question? As a world builder, the most likely reason is that you don't like that answer and would like to consider other options. If this is the case, then you're fishing for ideas (see #1). But what you don't realize, is that you're also biasing the answers. It may seem trivial, but how you ask a question is very important. It shows us that you've thought the issue through and you have a good reason (other than writer's block) to ask the question. Please remember that everyone here is a volunteer. We're delighted to answer questions! But that doesn't mean we are a free research team. Providing us with your existing answer suggests you haven't done some necessary research (or, at least, some necessary thinking) and that there's a deeper issue that we won't understand that needs to be addressed. To make a long story short, why was your answer unsuitable? Finally, please note that "I just don't like that solution" and "it's been done before" will rarely be appreciated as good reasons to ask for more insight. Remember, you're supposed to have thought this through first.
Our Help Center explains "the goal of the site is to help you build your world, not to tell your story." We are here to help you develop the rules and systems of your world. It may seem counter-intuitive, but we are not here to help you write your story. In the Stack Exchange universe, a problem is something specific, well defined, narrowly scoped, and answerable. "How do I cut a 33° angle on a 2x4?" asked about a problem. "How do I build a house?" is not a problem in SE's universe. Our Help Center further explains that questions must be specific and answerable, must include context, must include restrictions/requirements, and should include research. Questions that don't meet these expectations are often closed as "Unclear" or "Too Broad."
We address open-ended and hypothetical questions in our Meta posts about high concept questions and open-ended questions. In a nutshell, both are intrinsically "too broad" and "primarily opinion-based." As mentioned before, our Help Center explains "the goal of the site is to help you build your world, not to tell your story." Hypothetical questions are certainly an attempt to solicit our help with your story. And open-ended questions, at the least, violate Stack Exchange's premise that it is not a discussion forum.
Finally, rants happen. Especially with politically hot topics. Examples that we've seen here are questions about climate change and gender politics. You, the author, may be trying to write a legitimate story discussing these or other social issues of our day. That is perhaps the single most common reason for writing in the first place! But! Stack Exchange is not the place for an argument (even if it's disguised as a polite discussion in comments). We're not here to be convinced, pro or con, about how you feel about the issue.1 We are here to help you develop and consistently use the rules of your world. We're willing to set our politics beside the door if you are so that a good, well-formed question can be answered. We'll remember that we shouldn't argue if you remember that you might not like the answers we give you. That's the fundamental problem with rants in disguise.
Finally, just to close the loop, a word about what makes a question "Too Story-Based." Questions fall into this category when...
- You ask "will it happen?" vs. "can it happen?"
- You ask questions about circumstances, actions, or plot.
- You ask questions about a single character (it doesn't matter if it's the janitor or a god).
Remember (yup, for the third time), the Help Center explains "the goal of the site is to help you build your world, not to tell your story" and sometimes authors can't see the difference because the world is their story. We had to draw a line, and this is it. For more information see Why is my question "Too Story Based" and how do I get it opened? and What is "narrative necessity" and how does it apply to worldbuilding?.
If you ever worry that your question may or may not be suitable for the site, please (please!) submit it to our Sandbox. The purpose of the sandbox is to help you craft the question so that it gets upvotes and favorites rather than downvotes and VTCs.
I know that was much more than you were looking for, but I can easily imagine other users coming to your question with different problems based on your title — which is a great title, BTW. So, I'm hoping you'll forgive my verbosity.
1 And we are not here to convince you, pro or con, that your position is right or wrong. If you encounter comments that are addressing your politics rather than your worldbuilding question, please flag it as "rude and abusive." Stack Exchange users should know better. However, take a moment to think the comment through before you flag it. There is a regrettably thin line between, "this is an angle to the issue you should think about" and "you're wrong, admit it!" EVERYBODY needs to act responsibly.