Offered purely as punctuation in this fascinating exchange of opposing views, and apologies if it has already been mentioned without me spotting it. Surely it is possible that the reason for the so-called "delay" (not the decision to do so) of five to six hours in offloading the Purser was to ensure that she was safely landed at the first US airport that was more or less en route, and with the prospect of a quick onward flight to ORD, rather than leaving her stranded at a foreign airport without proper back-up?
To pick an airport for a diversion by considering that someone who is a threat to the safe operation of an aircraft might get stranded and inconvenienced at a foreign airport if off-loaded would demonstrate, as I said earlier, poor decision-making, nothing else. A threat is a threat is a threat.
If the CA was concerned about inconveniencing anyone, I find it more likely that he was concerned about his own fate. Off-loading the purser could easily have resulted in some sort of mutiny by the rest of crew (BoF said earlier in this thread that the purser had to talk the remaining cabin crew into continuing the flight for the sake of the passengers) - and being deserted by your crew in Miami is probably less annyoing than getting stranded at Salvador da Bahia.
Waiting for 5 hours, the captain obviously was not addressing a true risk, but held his own sort of court martial - instead of reporting the purser for insubordinance or demoting her on the spot. As I said earlier, all well within his authority, but probably sufficiently poor decision-making to cost him his job.