I was one of those that voted to close the question, so I can give my reasons, although I can't speak for the others. Please remember that these are my personal reasons for voting to close this question.
Firstly, the question doesn't actually show that the inclusion of Easter Island Moai Culture in comics is a particularly Japanese phenomenon. The list you linked to actually states that:
"the popularisation of other Easter Island cultural artefacts ... has occurred predominantly in the cultural economies of the USA, Japan, and Western Europe"
That list includes many non-Japanese examples, including (for example):
- G.I. Joe
- Montana Jones
- The Real Adventures of Jonny Quest
- Les Aventures de Blake et Mortimer [The Adventures of Blake and Mortimer]
- Superman: The Animated Series
- Justice League
- The Simpsons, The Critic, Futurama, and American Dad
- Rick and Morty
- Inspector Gadget
- Wacky Races
This point was also made in the (now deleted) comment by Aaron Brick.
So, did the images first appear in Japanese comics, or elsewhere? (If backed by some preliminary research, that might actually be a good question). When did that popularisation begin to appear in 'the USA, Japan, and Western Europe'? (Again, if backed by some preliminary research, that might also form the basis of a good question).
As it is, the question presented an assertion (that Easter Island such a frequent participant in Japanese Comics - at least relative to other cultures) without much in the way of evidence to support it.
Secondly, when I read the question it seemed to me that the images may well simply be a kind of shorthand for "Polynesian culture", or "Pacific Islands". This would be in much the same way as comics and movies generally show the Palace of Westminster, Tower Bridge or a Routemaster bus to say "Now the story has moved to London", or an image of the Eiffel Tower when they want to say "Now we're in Paris".
In my opinion, questions about why those particular objects and places have become sufficiently fixed in the popular imagination to act as that kind of shorthand are probably not generally well-suited to a site like History:SE (although there may well be exceptions).
Equally, it may be that many people find the statues exotic or enigmatic, and that element of 'strangeness' is, in turn, attractive for fantasy stories and comics. Again, if so, then the question of why that is the case may not be a question well-suited for a site like History:SE.
In my opinion, simply tacking the phrase:
"Are there any historical reasons for it?"
to a question doesn't necessarily make it a good question for this site. At the very least, provide some evidence that the question might be one that can be answered using historical methods and sources.
When I read the question, almost every interpretation seems to make it a question about 'social sciences other than History'. So that was the close reason that I chose.
Now, although I felt that the question was off-topic for this site, I didn't feel it was sufficiently bad to warrant using my moderator 'super-vote' to close it. As a general rule, I prefer to let the community decide. However, when it came up in the normal way in the review queue I simply added my 5th-vote as a regular user of the site. As Mark C. Wallace mentioned in his comment, "discussion and deliberation" aren't generally part of the stack exchange close-vote process. The question of using comments to improve feedback about why questions are closed has come up several times here (for example Comments discussing reasons to close? and How to improve feedback?). For now that question remains unresolved.
As for your comments, I simply didn't see them at the time (they were posted 3 days after the question was closed) which is why I didn't try to answer them.
[As mentioned in T.E.D.'s answer, there is an auto-flag that mods get if a question is closed without comment. In this case, I suspect that Aaron Brick's (deleted) comment meant that a comment had been posted and so the flag was not triggered.]
For what it's worth, in this case the close votes were posted over a period of 24 hours. After that, comments asking for feedback may not be seen. Once a question has been closed people simply may not have any reason to return to it and see subsequent comments.