Narrowing the interface helps, but the other "interface" is how the linker resolves names to specific addresses to code or data. The example I mention involving mutexes does not require those mutexes show up in public interfaces or necessarily "break" ABI guarantees. The mutexes don't even have to be used by the same source files! I guess you could consider it a library design flaw, but it's basically never mentioned as a design antipattern if it is one.

Note that it's not just mutexes. The same can happen with other kinds of "one per process" resources: memory pools, thread pools, connection pools, caches, registry objects, etc.