It's called "Gates" cause that's what it was called the first time I ran it in 1970. An old fart who ran it with me told me that's what the old farts who took him on his first trip called it.
Gates of Ladore
The Gates (emphasis on The)
Canyon of Lodore
Unless that is, you were a little old lady in tennis shoes from Pittsburgh on her first trip west of the Mississippi. As I recall, they also could be expected to refer to us as "Captain", but both issues were quickly addressed and did not cause animosity on anyone's part.
How times have changed.