My thinking is this topic is a difficult one, because not every "real world" question is on-topic for Worldbuilding, but neither is every such question off-topic.
Questions about Earth's history are explicitly off-topic in the help center. Questions about modern Earth can be on-topic, if worded correctly. Questions about applying real physics to the arrangement of fictional celestial bodies is definitely on-topic.
There's no cut and dry answer, which is why we can't seem to come to a consensus. The problem is, no one can really put in words where the limits of that gray area are. This is why your second linked question doesn't yet have any answers.
I've long taken "real-world" questions on a case-by-case basis, upvoting, downvoting, and VTCing as I believe appropriate, but I don't have any metric by which I judge the merits of the question that I can put into words.
So while we can agree that we need to come to a consensus on the topic of "real-world" questions, the range and variety of such questions is such that a general consensus may not be possible.
To explicitly address your questions:
Should it be as simple as the votes?
No, because the two answers only represent two aspects of the problem at hand. I believe the best answer is somewhere between the two (see above reasoning). A debate might be the best way to go forward from here, but don't look to me to participate much (if at all), since I'm terrible at coherent rapid-fire logic.
Once a decision is made how do we communicate it[?]
Umm... Honestly, I have no idea. I'm fairly certain a large portion of the site's users don't go deeper into the site than their own questions, and I know not every new user reads through the help pages. Sure, we can tag a question as featured and put the information in the help center, but that doesn't mean the users who need to see it do. It may simply fall to the users who monitor the Meta to propagate the information as "real-world" questions continue to appear on the site.