I know exactly what you mean with "different questions" but having the same cause and solution.
This same story is repeatedly happening, over and over, in VBA/Excel tags when people tend to repeat the same logical error when deleting rows from sheets.
This question is not very specific (and probably not the greatest example but most recent I found) but by just looking at the last loop in the provided code I kind of get an idea what is wrong with it.
I could go on and on about what could possibly be improved in the code but then if I were to answer this it would make both the question and the answer too localized, at least for my liking. It wouldn't include nothing new, nothing that has not already been mentioned (asked and answered) on Stack Overflow...
Such questions are asked multiple times a week. Most of the time, yes, they are all different questions but the cause and solutions almost always can already be found on Stack Overflow: all it takes is a quick search on: backward iteration.
The real problem is most of the users who ask questions on C#, Java, F#, Ruby on Rails etc are already somehow familiar with a programming dictionary. They know how to come up with 2, 3 words to describe their specific problem - like backward iteration. In questions tagged with Excel/VBA, most of the time you deal with power users not proper programmers which explains why their questions aren't too clear to begin with or/and too specific and it takes more time and effort from answerers to actually narrow the question down to a specific problem using comments section.
The comments question is great for giving the OP an idea of what is wrong and what to do/link to an existing solution. Once he understand what is causing the problem for him and sees a good answer that already well explains the core concept I think he will be able to go off and figure out the solution on his own.
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This is just my preferred way of dealing with questions which in the end lead to same answers.
Additionally, if a new problem/ a problem further down the line is discovered and something is unclear then yes, a good answer to a specific problem is definitely the right thing to do.
Solving problems this way you're not only saving your own valuable time by not duplicating an already existing answer but also you make Stack Overflow a better quality site.