Let's see; just as a preliminary matter, the following is how I read the "bottom line votes" of each user: 

 #Mayumashu (nominator): upmerge all 
 #Postdlf: upmerge all, except Category:Sportspeople in Columbus, Ohio 
 #Alansohn: keep all 
 #Mike Selinker: upmerge all 
 #Closeapple: keep all 
 #Vegaswikian: upmerge all 

 In summary and as merely an indication of "vote count", the results (as I interpreted them) were: 
 *Upmerge Category:Sportspeople in Columbus, Ohio: YES 3–3 NO 
 *Upmerge the rest: YES 4–2 NO 

 The reason I read Mike Selinker's vote as "upmerge all" was for the following reasons: 
 #His bolded vote said "Delete/upmerge"; and 
 #He said, "I think categorizing the individuals by city is too specific," which I understood as applying to all the categories under discussion, because all of them categorize individual sportspeople by city. 
 Maybe Mike Selinker could be consulted to see if I misinterpreted his comment; it is, of course, possible that I did, though on a second look I still don't think I did. 

 Leaving aside Category:Sportspeople in Columbus, Ohio, the following arguments are ones that I gleaned from the commenters: 
 From the "upmerge" side: 
 #Not part of a larger categorization scheme (Mayumashu; Vegaswikian); 
 #Categorizing sportspeople by city is too specific (Mike Selinker; Vegaswikian) 
 #Overcategorization issues: categorizing people in this manner will lead to articles being in categories that are not defining for them (Vegaswikian) 

 From the "keep" side: 
 #Categories are well-organized and well-populated (Alansohn, Closeapple) 
 #A high proportion of articles in one of the parent categories are sportspeople (Closeapple) 
 #A wider scheme would be sustainable (Closeapple) 

 My assessment of the arguments: 
 From the "upmerge" side: #1 is true and is relevant, though not determinative and should not to be given any great amount of weight. #2 is relevant but essentially a judgment call; however, it is one that was not really challenged by anyone else. #3 is significant and gets to the heart of the problem, and ultimately was the most convincing argument for me. 

 From the "keep" side: #1 is true and relevant, though not determinative and should not be given any great amount of weight, since many well-organized and well-populated categories are deleted. #2 was true for one of the categories, but was not true for the others and would not necessarily be true for similar categories for other cities, as Vegaswikian pointed out. #3 is relevant but essentially a predictive judgment call, and is not a particularly weighty argument. 

 My conclusions 
 It wasn't a great discussion, and much of it focused on Category:Sportspeople in Columbus, Ohio, which I haven't discussed above and for which I saw no consensus. For the rest: on balance, the upmerge side had the stronger arguments by far. Neither #2 and #3, either of which could theoretically justify the deletion of the category on policy and guideline grounds, were not challenged. The keep side pointed out some virtues of the categories, but nothing that was particularly convincing or based on a policy or guideline. The strength of the arguments, combined with the 4–2 "vote count" in favour of upmerging, led me to make the decision I did. 

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