This means, for example, if one wants to match against the files 'foo1' and 'foo99', it is required to use a match of "*foo*", rather than just "foo*". Ie. you have to match against an arbitrary initial pathname, just to match a part of a filename. The test suite unfortunately misses this case.
The match option is worded to imply matching filenames, as opposed to directories. A user that wants to match specific directory trees can simply supply just those directories as arguments. And they can exclude subdirectories with the -x option. So to me, it makes sense to change the match option to match filenames as implied.
The fnmatch module does allow matching against strings such as "foo/bar*", ie. it allows path separators. So if possible, we could also say that matching against a directory would require using the path separator in the match string.