Comment 1 for bug 1906584

It's debatable. We're trying to accord with Unicode, not with an obsolete spec that didn't fully anticipate characters that themselves are neither upper nor lower-case, but have a way to convert to upper or lower case.
To take one of your examples, https://www.compart.com/en/unicode/U+01F2 says that
(code-char #x1f2) has an upper-case character (#x1f1) and a lower-case character (#1f3).