Earlier quoted context omitted.
It seems to be mostly about math, with the only mention of array indexing being that 0 looks nicer. "starting with 0, however, gives the nicer range 0 ≤ i This doesn't seem to be much of an argument so I'm not even sure what to address.
How would you do something like Python's `x[0:10] + x[10:len(x)]` in a 1-indexed way? [1:11] + [1:len(x)+1]? That's uglier.
The best of both worlds is when a language provides both end-exclusive and end-inclusive slice syntax, as in e.g. Nim: x[0..<10] is end-exclusive, and it's very clear that it is.