That doesn't follow.
Beginners need to learn list slicing to get anywhere with Python, and by the time they've got through [1], [0:10], [2:], [:5], [:-1], [0:10:2] and so on then [:] is just another use in the same pattern.
Followup: The tutorial didn't seem to mention what [x:y:z] does, so I checked:
>>> range(15)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
>>> range(15)[0:10]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> range(15)[0:10:2]
[0, 2, 4, 6, 8]
>>> range(15)[0:10:3]
[0, 3, 6, 9]
These are "extended slices" and the third argument is the step. This link also explores deletion and the __getitem__ method:
One can also now pass slice objects to the __getitem__ methods of the built-in sequences:
>>> range(10).__getitem__(slice(0, 5, 2))
[0, 2, 4]
Or use slice objects directly in subscripts:
>>> range(10)[slice(0, 5, 2)]
[0, 2, 4]
them = things[:]
looks different from
them = (list) things;
which in C-like languages usually does not make a copy of things.
Using slices may avoid fallacies like "I know that int(x) is something like a cast of x to int, so list(x) is like a cast of x to list, which does nothing when x is a list".