It's not an implementation detail, it is a deliberate, specified and documented feature of the language dedicated to namespace conflict resolutions in the context of inheritance.
It's so crude that, again, it looks like implementation details having been promoted to specs. Field visibility and name mangling done with very magic underscores just doesn't look right, to me.
Which is my point, it's still roll-your-own, with some magic when necessary. I don't want to make a fuss about it, I mean, it's great for tinkering or small projects, but I prefer when my compiler works harder for me and actually enforces what is intended (bar some runtime reflection for very special cases).
Or it's just a philosophy that you happen not to like, which doesn't make it objectively bad or wrong. There's room for people to have different tastes and preferences.