... turning it into a cool genre movie or show? It can be a person, event, myth or even a symbol (like a country's flag or shield). This happens more often in the super-hero genre, but not always (like this year's GODS OF EGYPT). I ask because I've read/heard from time to time people saying that it's disrespectful.
shareHappens in SF too, although perhaps more so in books than in film/tv. Roger Zelazny did Lord of Light [Hindu and Buddhist myth], and Creatures of Light and Darkness [Egyptian myth]. Emil Petaja wrote a four-novel series based on Finnish myth. Lester Del Rey's Day of Giants plays with Norse myths.
Alternate history is generally seen as a sub-genre of SF. World War II, the American Civil War, the Thirty Years War, the Roman Empire, and more have all been the settings for alternate history stories. In addition, time travel stories seem to be drawn as if by magnets to pivotal moments in human history: e.g., the new show, Timeless.
I recently read a book by Taylor Anderson which is part of a series called "The Destroyermen," in which a USN destroyer and crew serving during WWII are shifted to another universe quite different from ours. There's a story in film development right now about a platoon of marines who go back to Imperial Rome. Twilight Zone had an episode about a US tank crew showing up during the Indian Wars.
So, it doesn't seem that unusual to me. As for how I feel about it, pretty much I feel the same way I do about any book or movie. If it's well done, I generally enjoy it. The recent fantasy/SF treatment of the Noah story was crap, despite the casting of Russell Crowe, whom I usually like. However, the show from a few years back, Kings, an SF alternate world version of the story of David and King Saul, was quite enjoyable. So for me, it's not the idea, but how that idea is executed, which determines whether I like it.
I wouldn't say it's disrespectful. Doctor Who took a lot of things from real life and "science fictionalised" them. The most prominent example would be the Daleks - their hate-filled delusion that they are the supreme beings is clearly analogous to the Nazis.
Certain Doctor Who stories "explained" the origins of some of Earth's myths. The episode "Pyramids of Mars" is one example. Other stories that borrowed heavily from Greek myth are "Underworld" and "The Horns of Nimon", which is basically a SF version of the Minotaur in the labyrinth.
There was also an alien invasion miniseries in the 1980s called V. Essentially a SF retelling of World War II and the Holocaust. The aliens have a symbol on their uniforms that looks suspiciously like a swastika. "To resistance fighters past, present and future - this work is respectfully dedicated" it said in the opening credits.
https://en.wikipedia.org/wiki/V_(1983_miniseries)
I remember watching V when it was first shown thinking this all seems a bit familiar!
"A big ball of wibbly wobbly, timey wimey stuff" The Tenth Doctor explains all.