The viewpoint being addressed here is what exactly? That STEM is a useful word with a meaning? I think rather than "trying to address" this viewpoint it might be more accurate to say you're trying to squash this viewpoint and prevent people from expressing the idea that STEM allows them to express. But maybe we expanded the definition of the word "address" to include this connotation as well, I have trouble keeping up with all the linguistic prescription going on these days. It's true that the arts aren't really the "opposite" of STEM, but if you took every usage of STEM, and replaced it with STEAM I suspect you'd change the meanings of all of those sentences in a very non-negligible way, which is to say you'll prevent people from communicating what they were actually trying to communicate.