It has 13 answers including a high-voted accepted answer. So, just removing the word “best” from the title removes the "Primarily Opinion Based" issue and transforms it into the question that everyone who answered took it as, anyway. The accepted a answer never gives a ranking, but lists a variety of options!
To me, it still seems too broad, and I can't really tell the difference between the two close reasons (one requires opinions to choose the 'best' answer, one doesn't have a 'best' answer and requires opinions to choose). Either way, it's still a pretty open-ended question, as can be seen by the 13 answers. Specifically, it looks like a tech level was not specified, so things like syringes and nerve gas are offered as options alongside spears and knives. That, to me, is what makes it close-worthy.
But anyway, I stick to my stance that close is a reason to edit, not to give up. We close questions so that they can be edited without invalidating answers. At least twice I've tried to tell a new user that it's too late to fix their question, it's just going to have to remain closed forever because there's too many existing answers to fix it. If we'd closed it sooner, these users who come into chat or onto Meta to see what they did wrong can be given good advice, can improve their questions, and when the question is reopened they can get quality answers that show other new users the right way to ask and answer.
I think whether or not open-ended questions belong here is another question for another day. Right now, we don't allow it, we encourage well-constrained questions for which there is one or a small subset of good answers. With this in mind, I say we should close often, and reopen just as much. Closing teaches askers how to ask good questions, and teaches answerers to hold off answering until the question is good enough. The users we lose to this are the ones who are unwilling to learn these things, who are too lazy to try to maintain high-quality questions and answers. And I don't think losing them is such a bad thing.