Probably the system of giving special meaning to what are otherwise ordinary identifiers. __ isn't a reserved keyword in Python or anything. But there's a set of conventions you're supposed to follow when naming methods and attributes, and they're visibly artificial. It would be cleaner to make the features that are a special part of the language definition also a special part of the language syntax instead of running them in indistinguishably with other nonsimilar things.
In C++, if you want to define the binary + operator on a class, you give the class a method with the special name `operator+`. In Python, to do the same thing, you give the class a method with the pseudo-special name `__add__`. You don't think the Python way is worse?
In C++, if you want to define the binary + operator on a class, you give the class a method with the special name `operator+`. In Python, to do the same thing, you give the class a method with the pseudo-special name `__add__`. You don't think the Python way is worse?