> In Python you can initialize a class with a constructor that's not even in the inheritance chain

No, you can't. Or, at least, if you can, that’s not what you’ve shown. You’ve shown calling the initializer of an unrelated class as a cross-applied method within the initializer. Initializers and constructors are different things.

> Oh, bonus point. I've see people creating a second constructor by calling `object.__new__(C)` instead of `C()` to avoid calling `C.__init__`.

Knowing that there are two constructors that exist for normal, non-native, Python classes, and that the basic constructoe Class.__new__, and that the constructor Class() itself calls Class.__new__() and then, if Class.__new__() returns an instance i of Class, also calls Class.__init__(i) before returning i, is pretty basic Python knowledge.

> I didn't even know it was possible to construct an object while skipping its constructor, but dumb people know this and they use it.

I wouldn’t use the term “dumb people” to distinguish those who—unlike you, apparently—understand the normal Python constructors and the difference between a constructor and an initializer.