Question

The codes are like this:

        if line.split(None, 1)[0].lower() == 'rem' and line[0] in "rR":
            # no leading whitespace
            continue

I think this means if I write a config like this:

[memo]
rem ember_last = True

The line starts with rem ember_last will be ignored.
Why was the ConfigParser designed like this?

Answer 1

rem in Batch is used to add comments, i.e. it’s a command that essentially does nothing. It seems that this decision was carried over to configuration files:

Enables you to include comments (remarks) in a batch file or in your configuration files.

However, rem and the actual comments are always separated by whitespace so it makes no sense that a configuration option remember would be ignored (only rem ember would). The code you posted confirms this, as the following shows:

>>> line = 'remember_last = True'
>>> line.split(None, 1)[0].lower()
'remember_last'

So, your problems seems to be something else.