It's bad because someone can think of a niche case where it can be abused. In my experience, it never happens. You tend to find that those smart enough to know how to overload say the = operator are also smart enough to only do it for a good reason.
I've seen bad developers utterly abuse just about every language out there, if there's a language feature then it can be abused. C++ just happens to have a lot of features.
Have you got a source to that? I know it has been suggested numerous times, but I've yet to see anything to state that it's actually picked to go into the standard.
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