Regarding the specific question asked: It should not have been down-voted, it should be close-voted. It fits the definition of "subjective & argumentative" (now known as "not constructive") precisely.
Though there's bound to be some subjective questions on this site, and a number of questions for which answers may vary by denomination or personal belief, questions like these stand out significantly from the rest. Answers will be very much based on whether or not an individual is a Mormon, or how a non-Mormon answerer considers the broader definition of "Christian". I'm fairly confident there is little to no Biblical coverage on the topic, and any such coverage would likely be a strong point of debate between Mormons and non-Mormons.
At best, the question is not at all a good fit for this site. At worst, it's a blatant example of trolling.
That said, now is a good time to refer everyone to the voting guidelines in the up-vote and down-vote privilege pages:
When should I vote up?
Whenever you encounter a question or answer that you feel is
especially useful, vote it up!
Consider:
- Is the post well-formed and specific?
- Is the post on-topic?
- Is the post objective - an objectively-answerable question, or an answer which is written from an objective, un-biased standpoint?
- Are there enough details given in the post - for the question to be answered, or for an answer to be useful?
- Does the post represent good research - a question presenting a particular challenge to the community, or a thorough and well-thought answer?
When should I vote down?
Whenever you encounter an egregiously sloppy, no-effort-expended post,
or an answer that is clearly and perhaps dangerously incorrect, vote
it down!
Consider:
- Does the post represent a distinct lack of research - a simple, Google-able question, or a short, opinion-based answer without objective support?
- Are there not enough details in the post - in a question for it to be answerable, or in an answer for it to be useful?*
- Is the post egregiously incorrect or mis-informative based on readily available evidence?
**In some cases potentially good questions/answers may still be lacking in detail. These can later be expanded upon, but in many cases a lack of detail is also an attribute of a bad post - especially for questions.*
What are the alternatives to downvoting?
Instead of voting down:
- If the post is spammy or offensive — flag it.
- If the question is duplicate or off-topic — flag it for moderator
attention.
- If something is wrong, please leave a comment or edit the post to
correct it.
Additionally, if a question qualifies for any other close reason it should be voted (or flagged) to close instead of down-voted.
I personally believe that if everyone would follow the above guidelines from a strictly objective point of view, most "vote contests" can be avoided.
It should be noted that it is fairly standard across StackExchange communities, for voting in Meta boards to often be an expression of approval/disapproval of the ideas presented in a post. This applies to questions as well as answers. However, this should not be carried over to the main site.
Some additional reading material:
http://blog.stackoverflow.com/2010/09/good-subjective-bad-subjective/
https://christianity.stackexchange.com/faq