I don't know of any single one that would work on all of the threads you tag that way, but I tagged this one "politics" and "geopolitics" myself, "foreign policy" might also fit.
For the others here are examples of what I'd tag:
You can go back in time and prevent a great catastrophe. Which one would you prevent? - history, time travel
If you went to a beach and it turned out to be a nude beach, would you stay and go swimming? - beaches, swimming, nudity, nudism, nude beaches
What is the oldest age you would like to be alive? - age, aging, death, life
If someone told you had exactly 9 minutes to live, what would you do in those 9 minutes? - death, life
Name three things you wanted as a child but never got. - childhood
When you drink milk and start laughing why does the milk automatically squirt out of your nose? - milk, laughing
I'm sure better tags exist for all those but those would be my first tries. Of course if any of them are actual fluff news stories "human interest stories" is a fitting tag.
My 2 cents.