Getting the hang of what is and isn't accepted on a site is never an easy task. Even seasoned users have some time struggle with one or another question. So you should not feel bad about having a question closed. I know it can feel like a personal attack, but believe me, it isn't.
If you are unsure about the reasons why a question got closed, do ask it here, or possibly on chat. But then ask for an honest view and take the time to read the answers you get.
To your point of suppressing the "primarily opinion-based" close reason (POB), we can't. This is common throughout the Stack Exchange network.
Now, to get on more specifics about why some of your questions were deemed POB, one should understand how stack exchange works. You ask a question and people can answer, up/down votes the answers to see which answer the best your question. But a naming question, for example, does not allow any objective voting. It is impossible to decide which of "cat" or "Bob" or "jdhmlkdse" would actually be the best. The only valid judge is yourself. You could have tens of thousands of answers, and people could still add another one.
Plus, the question should not be too specific, since it should also be useful to other people. This is why, on Writers, questions about generic name generation are accepted, but questions about naming a single character isn't.
At this point, I hope I could convince you that any "naming" question would be closed on the same way. Actually a few of those are lying around.
For the other 3, you present some decisions made by an alien species. And ask us to critique, suggest improvement, or share our opinions about it. Since, by definition, it is an alien species, we cannot know really what they value, why they would make such a choice, and why not another. The measurement units that we today in various countries somehow reflect the History of each country, and is often based on our anatomy (inch, foot, etc.), or on some arbitrary numbers (24 hours is great to divide it!). It is the result of a complex evolution. The same hold for a set of moral values. Now without knowing the alien species in many details, we can't objectively pick anything. We would need to recreate the whole evolution of that alien species. And we don't know the reasons behind the first choices they made.
So yes, many questions on Worldbuilding are Opinion-based, but most of them can be answered by a combination of scientific knowledge, from physics to politics, from philosophy to computer science. Those are the best answers, and people can objectively judge (vote) if those are more or less appropriate to answer the question asked.
The Sandbox and the chat are great places to run your ideas and concepts of questions before asking them.