That doesn't explain the dreaded Toronto dislike. They're still The Toronto Blue Jays and Toronto Raptors.
There's a documentary that tackles this very topic called "Let's all hate Toronto." I've never seen it myself, but I bet it'd be an interesting watch. Hell the whole mindset of the rest of Canada would make a great case study.
Without getting too political, Tom Mulcair a politician running in the upcoming federal election recently called Toronto "Canada's most important city." While some people didn't care and actually agreed, some people really disliked the comment, and others said it was a bad move politically. But why? Is it really impossible to talk about Toronto in a positive manner in other parts of the country?
It's such a crazy phenomenon. I wonder if other countries hate on their biggest city as much as the rest of Canada does here.
To answer your question, I think people have a strong dislike of Toronto because of the massive media attention the city garners. In regards to sports, the Leafs are covered quite extensively on the major sports network. Toronto was also for the longest time Canada's only major English speaking metropolitan area. It's only the past decade and a half that Vancouver has caught up, with Calgary following close behind.
There's also this perceived notion that Toronto isn't really Canada, whatever that means. If it's in regards to rude people I don't see the difference between downtown Toronto and downtown Montreal or Ottawa. Of course, the notion that Toronto isn't Canada is a fickle mindset. Remember that Leafs game where the American anthem singers microphone went out, and the arena in classy fashion finished it off for them? Boy there was a hell of a lot of pats on the back and Canadian pride and patriotism online with regards to that. People quickly forgot about that though when a video surfaced of a cop diffusing a road rage incident and the comments were "It's Toronto, of course this happens."
This post is longer than I wanted it to be. The last reason people dislike Toronto is the perception that Torontonians are self absorbed and arrogant. This stereotype his hand in hand with a lot of other major cities, so that just comes with the territory. And honestly, that last sentence really sums this whole thing up. The hate Toronto receives is the result of being a large major city.