That this is possible means that anybody who doesn't want to be found this way should always use the same language as everybody else. If you call Voldie ‘Voldemort’ (or ‘Tom Riddle’ or even ‘Voldie’) when everybody else is calling him ‘You-Know-Who’ (or ‘He-Who-Must-Not-Be-Named’ or even ‘The Dark Lord’), then you're holding the Idiot Ball. (And it doesn't have to be the caster's name; you shouldn't use any unusual words, or you can be tracked by them.) Not that canon!Dumbledore was holding the Idiot Ball in books 1–6, because this was not possible then; Rowling hadn't thought of it yet. But MoR!Dumbledore seems to be, unless MoR!Taboo works differently.

A good way to balance the Taboo spell might be this: It only works if the speaker knows about the Taboo (although this contradicts canon). Then you can get a nice dilemma: Do you tell people about the Taboo here at Hogwarts, where it's safe so they can practice, but opening them up to the curse later; or do you keep silent, and hope that they aren't surprised by that information later and disoriented thereafter.

Sure, but Harry has no clue that's possible. What actual reason does he have to be afraid of the word? Not a reason we can come up with for why that fear is positive, but one internal to Harry's mind.