Obviously, plagiarism is not okay, so you could always try to have questions deleted on those grounds. That being said, if the post is significantly more than just a link to the Temple of Quetzalcoatl -- if the poster has rewritten the question sufficiently and cited it -- I'd have trouble being convinced that the question isn't suitable for this site.
Normally, posting puzzles here that are from other websites is welcomed so long as they don't exist on Puzzling yet, so this is an interesting one. I'm not completely familiar with Stack Exchange's policy on plagiarism, but copying of questions isn't a problem in most other communities. This question talks about copied answers, but that isn't quite the same.
From what I understand, if questions on Puzzling follow the same rules as answers, I don't think there's any valid reason they could be deleted so long as the poster cited the source and didn't just copy-and-paste the question.