I'm also a little confused as to why colorizations always aim to restore color to the equivalent of a faded color negative, with muted tonality and grain. Human logic is funny.
I always assumed that if you tried to use "full color" it would look weird, since the photos themselves usually are quite faded and grainy.
More than that, it would look weird because restoring the color to a photo in a way that looks plausibly photorealistic is really hard. If you make something more stylized, the viewer doesn’t have as much reference to compare and realize that there’s something wrong.
To the grandparent: people have been trying to colorize black and white photos since the 1840s
True. But there was also tons of skepticism in the medium throughout the mid- to late 1800s. Oliver Wendell Holmes' writing on veracity of photography is a neat reminder that it took the public decades to come to terms that the photographic process was a somewhat-veritable facsimile of "real" life.
I always assumed that if you tried to use "full color" it would look weird, since the photos themselves usually are quite faded and grainy.