Based on what I learned a few months ago trying to deal with all these problems, the conclusion I've come to is that basically the entire "standard" set of POSIX calls are wrong. Correct handling requires an entire parallel set of calls like "openat". However, this parallel set of calls postdates the more conventional calls by a couple of decades and in some cases we found may still not yet be entirely complete. (I'd guess they probably are by now, we were a couple of versions back on the kernel.)

The problem is that those old calls have immense, immense inertia. They are how people think of files. They are how almost all, if not actually all, higher level languages interact with files by default, saving the "correct" calls for external modules, if you even get that. In fact, many higher-level languages are actively inimical to correct file handling by trying to abstract away the "file handle" so you only have to deal with file names, but for correct handling you really need to consider the file handle the real file and the file name merely a transient method for obtaining a file handle, which is to be never used again once you have the handle.

Bear in mind the "crappy" API in question is probably older than you are, so it's not really that surprising that it has needed some work as our world has changed.