> the Python code in the previous example is still readable

Yes, I agree with the author, list comprehensions are readible, and I'd add, practical.

> it gets worse as the complexity of the logic increases

    len(list(filter(lambda line: all([abs(x) >= 1 and abs(x) <= 3 for x in line]) and (all([x > 0 for x in line]) or all([x < 0 for x in line])), diffs)))

Ok, well this is something that someone would be unlikely to write... unless they wanted to make a contrived example to prove a point.

It would be written more like:

    result = sum(my_contrived_condition(x) for line in diffs)

See also the Google Python style guide, which says not to do the kind of thing in the contrived example above: https://google.github.io/styleguide/pyguide.html

(Surely in any language it's possible to write very bad confusing code, using some feature of the language...)

And note:

    x = [line.split() for line in text.splitlines()]

^- list comprehension is just a convenient shorthand for a `for loop`, i.e.:

    x = []
    for line in text.splitlines():
        x.append(line.split())

Just moving the `line.split()` to the front and removing the empty list creation and append.