The issue is that operators rarely have obvious semantics when applied to non-builtin types. '+' makes sense for integers and floating point numbers, complex numbers and ratios, and almost nothing else. Those types can be built into the language, and '+' defined on them. It doesn't make any sense for strings and all the mismash of things people will overload it for.
I've never seen anybody confused by "+" for string-concatenation. It makes far more sense than, say, integer division where 5/3 = 1.
Just because C++ ruined operator overriding with their moronic << doesn't mean that every other language should live without perfectly reasonable operator behavior. I've been dealing with Java instead of C# and not being able to use simple obvious equality checks with the "==" operator is agonizing.
Languages should build in all the numeric types you could ever need, but they don't. A lot of languages still don't have arbitrary-size integers (Swift among them).
You see the vast majority of cases not needing operator overloading and see it as useless, while I see the small number of cases where it's really, really good and see it as important.
