I only talked about pinyin because Chinese familiarity with tones was brought up as a reason why some non-Vietnamese speakers might still recognize the diacritics and get some value from them.
But even beyond that, I highly doubt that the article is really ambiguous without diacritics. I somehow doubt that if the NYT talks about a Hoa Lo prison somewhere in Hanoi, there is any real ambiguity about the actual place they are talking about. Sure, the words in themselves are ambiguous, but the context makes them very clear. This is not about writing Vietnamese without diacritics, which I'm sure is extremely ambiguous. It's only about some place names with very clear context about where and what they are.
But even beyond that, I highly doubt that the article is really ambiguous without diacritics. I somehow doubt that if the NYT talks about a Hoa Lo prison somewhere in Hanoi, there is any real ambiguity about the actual place they are talking about. Sure, the words in themselves are ambiguous, but the context makes them very clear. This is not about writing Vietnamese without diacritics, which I'm sure is extremely ambiguous. It's only about some place names with very clear context about where and what they are.