Condé Nast Traveler is a luxury and lifestyle travel magazine published by Condé Nast published in New York.
So it is not surprising that San Miguel de Allende, Mexico was No.1 beause many US pensioner live there (pleasant climatic conditions at 1900m attitude).
And Victoria, Canada is popular with US tourists.
By the way the magazine distinguishes between small towns and big cities.
And among the major cities, Bangkok ranked second behind Singapore and ahead of Tokyo.