I often wonder why the faculty to imitate an accent (≈ speak phonetically correctly) and to speak a language morphologically / syntactically / semantically / idiomatically /… correctly seem to be so independent – and why the latter has so little impact on people's judgement.
(This case may be a bit different, as anything beyond the phonetics is probably not Bloomberg's anyway.)
In other words, why can you learn to speak a language correctly, except for the phonetics and prosody, and still sound like a fool. Why can learners acquire all the rest of it, grammar, vocabulary, etc... without acquiring the phonetics? Why do phonetics enter in so strongly into our perception of speakers, so that, for example, a person with a relatively slight foreign accent (to my ears) and impeccable grammar will be told sh/e can't speak English at all?
Why am I tolerant of people speaking English in a wide variety of accents, but relatively intolerant of accents of non-Hispanophones trying to speak Spanish? (Well, maybe because I'm a Spanish teacher, duh.)