

Toronto is definitively south-central, though nobody calls it that, instead saying GTA/GTHA/Golden Horseshoe, etc. I can’t find any sources that say Toronto is in Southwestern Ontario, so I don’t think there’s any support for what your saying (Wikipedia, Ontario Tourism for 2 counter examples).
Like Fort Frances is on the border and it’s Western Ontario but you would still call it Northern
Yes, because we first divide Ontario into Northern & Southern. If you just said Fort Frances was in Western Ontario, it would cause confusion which is why it’s “Northwestern Ontario” (EDIT Wikipedia also agrees with me on this one).
Authoritarians? You mean glorious communists! /s