I'm relatively new here, and I can't speak for those who closed the question.
However, even in the few months I've been here I've discovered that since its early, freewheeling days, Christianity.SE has gone through a major refocusing and tightening of its standards for the scope and focus of questions and answers on the site. At the time you asked that question, it was perfectly acceptable. But now, questions about Christian belief and practice must specify some sort of denominational scope, or at least ask for an overview of major positions on an issue.
Basically, the site has morphed from being about Christian belief to being about what groups and denominations of Christians believe. Questions asking for the Biblical basis of a belief are also acceptable. And questions about Christian history and the origins of various beliefs are on-topic as well.
The aim is to make the questions objectively answerable, so that they are about what groups of Christians believe, or about the Biblical basis of various beliefs.
Your question falls afoul of these more recently imposed standards and guidelines because it has no specific scope, and thus could be answered from a wide variety of individual perspectives.
In fact, though I didn't read all of the answers, I right away found myself disagreeing with major points made in the first (and accepted) answer precisely because it wasn't properly scoped. It presumed to speak for all of Christianity from what is really a specifically Protestant perspective that is not shared by the rest of Christianity--which is the majority of Christianity.
Though theoretically most old questions could be edited fairly easily to make them properly scoped and more objectively answerable by today's Christianity.SE standards, the problem comes when there are already a number of answers responding to the question as it was originally asked. Editing the question commonly breaks those answers because they no longer answer the question as edited.
This, I believe, is why the powers-that-be here on Christianity.SE decided that it was generally better just to close those old questions that now fall afoul of the new site standards and guidelines, but leave them on the site for historical purposes.
Once again, this is all from the perspective of a relatively new Christianity.SE user.