People seem to be confusing the concept of "The question title relates to the question" with "The question title is a literal question with a question mark." Ironically, this very question is a perfect example:
Title: How strict do we need to be about making sure that question titles reflect the actual question?
Actual question: Should we edit question titles to make them literal questions?
Yes, we should make sure that question titles accurately reflect the actual question. No, we should not edit question titles to make them literal questions if there is nothing wrong with the existing title.
Bulk-editing is disruptive to the site because it means that the "active questions" list is full of questions that are only active because they've been edited. This makes it harder to find new questions and answers and carry out the core functions of the site: answering questions and voting on questions and answers. Trivial edits are discouraged for precisely this reason.
Because bulk-editing is disruptive, it should only be done where there are actual benefits to compensate for this disruption. Giving a bad question a better title doesn't make it a better question: please don't do it; start a close vote instead. Editing an accurately descriptive title to make it a literal question doesn't improve the question or make it easier to find: please don't do it. Please keep titles concise. The title doesn't have to contain every nuance of the question: it's just a headline summary.
Justification based on the "question titles not phrased as questions" query on data.stackexchange IMO doesn't fly.
The text on the query page says, "This query MAY be useful for identifying titles that aren't phrased as a question or low quality questions." (emphasis in original) Note what it doesn't say. It doesn't say that the query identifies low-quality titles. It doesn't say that the query is useful for identifying low-quality titles. It says that the query MAY be useful for identifying low-quality titles. There is no rule or even, as far as I'm aware, recommended that question titles must be phrased as a question. There is a multiply-starred comment in chat pointing out that it is not necessary for question titles to be literal questions.
To take a recent example, "Maximum climb rate of an Airbus A320-200" has been edited to "What climb rates can the Airbus A320-200 achieve and which climb rates are commonly used for normal flight operations?" The original title was a perfectly accurate summary of the question. The new title is very long-winded (so takes up a lot of space in question lists, especially on mobile devices) and doesn't accurately reflect the contents of the question. The question actually asks what the maximum climb rate of the A320-200 is (surprise!) and if there's any commercial passenger aircraft whose climb rate can exceed 6000ft/min.
So, yes, by all means improve bad question titles. But "not a literal question" is not the same thing as "bad". Please spend your effort actually improving the site instead of just optimizing random metrics.