I actually have to agree if you are coming to something like

    a = b[:]

in code you are going to understand what it means or you are probably going to be missing a large portion of other things that are going on in the python code.

With that said I must also state that I think

    a = list(b)

is much prettier and is easier to understand to me.

They need to learn it, then. Honestly, anyone who read and comprehended my first post now understands slice notation (with the exception of the more rarely used stride argument), so it's not like it's a ton of effort. Unless the post author is claiming that slice notation itself is cryptic, I don't even understand where he's coming from.