Kingston is both an Army and a university town; at any given time a quarter of the population are students or soldiers, or both, so a disproportionate number of its residents are young, upwardly mobile, healthy, and more ethnically diverse than born-and-bred Kingstonians (“townies,” as the students call them.) That demographic is inherently attractive.
You’d find the same thing in any similar university town, like Kitchener/Waterloo or Guelph. Heck, walk around any city and when you’re near a university, people are visibly way more attractive than when you’re not near one.