> International relations is an actual subject area. It's true that we don't need that many diplomats
In my experience "International Relations" classes teach very little that's actually valuable. I think there's a common in mistake in thinking at because X is important, then university classes about X are useful. There are a lot of subjects that are important but where the study of it in academia (at least at the undergraduate level, but I suspect higher up as well) isn't handled well at all.
I think the mistake that a lot of people make, however, is thinking that this is merely a humanities vs. STEM issue. There also seems to be a lot (though perhaps not quite as much) useless classes in the STEM fields as well.
Worst of all, I've seen very little interest in academia (both STEM and the humanities) in whether or not their way of teaching is effective - its simply assumed to be, and that's the end of the discussion much of the time. It's claimed that academia fosters critical thinking, but there often seems to be a dearth of critical thinking from those who are within it.