"Trolling" implies intent, which is hard to judge when reading someone's words. So I agree with the generally accepted approach of taking things at face value: If someone asks an answerable question, we should focus on answering it rather than guessing intent. (Outside of obvious fringe cases, which should probably be handled with flags).
I think that still leaves us with a problem, with respect to the question you've linked to: Is this an answerable, on topic question for The Workplace?
I do think it passes the test of being on topic in terms of the subject matter. How you measure someone's performance is clearly a workplace problem.
To me, that is the most important factor to consider, because other factors (is it to broad, is it opinion-based, does it have a clear goal, etc) are, often, easily handled through edits. If someone asks,
Do you think X is a good measure of performance?
that is pretty blatantly opinion-based. It shouldn't matter what I think, it should only really matter what general truth I can describe or what experiences I can speak to, or what references I can provide. Or maybe the person asks something that's too broad:
How should performance be measured?
But ultimately I think those are weak reasons to close the question, because we all inherently know what the person is actually trying to get at, and I don't think it's fair to close a question purely because of the words the author chose when the actual subject they're asking about is on topic. So, perhaps we can suggest that the OP rephrase the question, or we can edit it to keep the wording on topic.
Ultimately, I think this is what you were getting at in comments when you said,
in fact, think you are correct in that "lumberjack's productivity is measured in lumber, why can't we measure coder's productivity in lines of code" is a valid and good question
Perhaps this question could be saved by editing to reflect that.