https://superuser.com/questions/284021/remove-documents-from-main-library-on-kindle

I think this is a legitimate question about a piece of software (the Kindle's OS) which was abruptly closed by a mod with an unhelpful and somewhat disparaging comment.

Questions on Super User are expected to generally relate to computer software or computer hardware, within the scope defined in the faq.

It doesn't seem like there is a no-Kindle policy here, I see plenty of questions regarding them.

So why was this closed?