v0.28 of List Item spec is too complex to understand.

http://spec.commonmark.org/0.28/#list-items

See the rendered result of the code:

100. foo
    * bar

babelmark: https://babelmark.github.io/?text=100.+foo%0A++++*+bar

which is not nested but flatten in commonmark, as the spec says. This is the spec, but whoever wants this behavior? I don't know the editor that can make a nest with a single TAB key. I think it is a specification problem because it is a too complex rule compared with other markdowns.

Why didn't the spec define "nesting lists require 2 spaces" (or "4 spaces")?