To the best of my knowledge, the relevant road has never officially been named the "Alcan"...I'm more than willing to be corrected on that....but what I understand was that it was called the Alcan by the GI force that built it.
At least that's what two of my uncles who were part of that force (1 a catskinner, 1 a timber feller) told me in my so-long-ago tender youth. Rightly or wrongly, back in the day in Alaska circa '60's and '70s, the term Alcan was used as a measuring stick: "Is that truck dependable enough to drive the Alcan?"
Even back in the '60's (if fading memory doesn't play tricks) there were bumper stickers proudly proclaiming "I drove the Alaska Highway".
So I don't know that it is political correctness.
All that being said, I'm lazy and getting old, certainly stubborn, so I'll probably go on calling it the Alcan.