Checking in code the right keyword is "enabled" and not "enable".
In addition the comment was also completed:
This could appear useless because the "defaults" sections not
yet apply on "peers" sections, but it could be the case in the future.
This statement can currently cancel a previous "disabled" keyword in
the same section.
This patch should be backported in all supported branches (keyword
is present since 1.5)
620761f934