This question already has an answer here:
Questions such as these should have been voted for closing/deleting instead of putting on hold, when it's seriously unconstructive, e.g.: http://meta.stackexchange.com/questions/214115/why-should-you-downvote-this-question
So my question is, why put on-hold instead of voting to close/delete them in the first place?
How should moderators decide whether a question should be on-hold or closed/deleted, what is the line?