Many of them are better at being unix-y because they are Unixes or Unix clones.
Apart from Windows, which squares remain if one removes any Unix/linux derivative?
The real joke is that people defending Windows' oddity by saying it's a VMS clone, where curl authors apparently consider actual VMS an easier platform to support.
Mac OS 9
DR DOS
OS/2
VMS
Windows CE
z/OS
MorphOS
Atari FreeMiNT
OS/400
[...]
Actually probably a fourth (EDIT: after looking more closely, make that ~half) or so of the list are not in any way UNIX.