Believe it or not, there are variances in people's bodies that cause some to smell more and some less. Some of the variance is known to change with age (see 'Old Person Smell' on Wikipedia). I presume the rest of the variance is due to genetics, microbes like we are discussing here, or other unknown factors.
Some people obviously require a strict regimen of daily soaping, powdering, de-odorant, and re-odorant (perfumes etc) or they become grossly offensive. That does not necessarily mean he is the smelly guy in the office - just that he can become the smelly guy without the aforementioned mitigation efforts. So, in no way is this meant as a treatise against deodorant. Some people need it.
Some other people do not need to coat themselves in these products on a regular basis to stay inoffensive. For whatever reason they do not produce the same quantity and/or quality of odor. In a low-activity lifestyle these individuals may not need more than a daily water rinse, with occasional more thorough cleaning as-needed.
I'm also curious about your anecdote, was this gentleman aware of his odor? If so, how was he made aware? You mentioned a second opinion from an unbiased source, can you be more specific?