But there is southern Alberta, southern Saskatchewan, etc., no?
First there is absolutely no way that in Cuba and Mexico Cortez did not kill far more people than Montezuma. He played a big part in wiping out upwards of 90% of the population of both places, the Aztec empire was no peaceful utopia, but they were compared to the Spanish conquest (those non-Aztec groups that allied with Cortez because they had been victims of the Aztec empire very soon regretted their decision)
Secondly yeah, the song does not go into the details of the violent nature of the Aztec empire, but its a (completely justified) polemic against Cortez and the conquistadors, that’s the nature of a polemic, its pretty hard to write a catchy song (or even a slightly noodely overlong song, in Neil Young’s case 
) railing against some great injustice if you have to add a footnote that says “but actually the opposing side were also not perfect and had some pretty serious issues, which I’ll now lay out …”. You can’t criticize a songwriter for not doing that IMO.
The anti-war song about the Vietnam war I was Only 19 contains the line:
‘Then Frankie kicked a mine the day that Mankind kicked the moon
God help me (he was going home in June)’
Mankind kicked the moon on July 20 1969 (I suppose Frankie could have been going home next June, but I think it’s more likely a lyrical device because not much rhymes with July).
In the song Raised on robbery, Joni Mitchell sings:
First he bought a '57 Biscayne
He put it in the ditch
He drunk up all the rest
That son of a bitch
Chevrolet didn’t make a Biscayne model until the 1958 model year. (I know only the pickiest of car guys would get that one) 
File that under topological errors that bug me. Seriously Pete is Chiswick non-Euclidean? That’s news to me
If you lived in north portal Saskatchewan would that not qualify as “southern Canada”? (Although I agree I’ve never heard of “southern Canada” having any regional significance)
I always say that I (in Vancouver area) live in the Pacific Southwest, because it is—of Canada.
Since cars are released prior to 1 January of their model year, the owner still could have bought it in 1957, perhaps?
He could perhaps have purchased the car in later 1957 but it sill would have been a 1958 model year as the Biscayne name plate wasn’t used until the 1958 model year.
While you guys argue about that, the real historical error in the song is the alleged gun fight between Capones gang and the police resulting in over one hundred cops dead. It never happened.
Especially when the snowdrifts cover the windows, we like to call ourselves Baja Canada.
Right, there is no region KNOWN as …
But of course there is .
I don’t get it. Some parts of Chicago are further east than other parts. Obviously. There may not be any area that is officially called East Chicago but there must be an east Chicago. Isn’t there an east everywhere?
Not at either Pole
The first thing I thought of after reading the OP were all the Schoolhouse Rock! songs on the subject of America.
I have mentioned this already. No use getting into the middle of a silly argument, no one cares.
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The singer is the cop’s son, quoting someone who heard something, probably from someone. The song isn’t claiming it was the truth. You know how rumors go?
Hate the song because you hate it, but don’t make up reasons.
Snoopy could not have fought the Red Baron, as Snoopy was born in 1950 and the Red Baron was killed in 1918.
Some things are annoying even if they are fictional. That Hyacinth Bucket was meant to be annoying doesn’t make her less annoying nor make Keeping Up Appearances any better of a show.
Then again, sometimes the gambit of putting unbelievable words in a character’s mouth where it isn’t immediately obvious that the author does not necessarily believe it themselves does work for me, and there isn’t any hard and fast rule as to when I like it or when I don’t like it.
Mother and son hear a rumour that 100 police were killed. They get scared thinking the husband/ father is dead. Cop comes home and is unhurt. The rumour that 100 cops were killed turns out not to be true.