The answer to all this, of course, is scale. Brazil has over 200 million people. It is, for the most part, a ferociously poor country. Violent crime is inevitable, especially after things were ramped up by crack cocaine, drug rings and shootouts.
It's also true to say many Olympics and Commonwealth Games have faced problems pre-Games leading to much wringing of hands but which proceeded OK: Los Angeles, Seoul, Barcelona, Athens, Beijing. LA was supposed to be ruined by the Eastern Bloc boycott. Nah, although the 1980 Games in Moscow were definitely deflated by the Western boycott (an admittedly Western perspective).
Seoul 1988 was subject to fears of the evil North Koreans with stories of the dam near the border which would flood Seoul if the north pulled the plug. I wrote one of those stories myself. In 2005, the south was flooded when the north, accidentally or deliberately, let gazillions of gallons loose. South Korea responded by finishing the Peace Dam in 2014 - the world's only dam constructed to guard against another dam. It has no dam-able water supply of its own. It exists only to counter the flood that will likely now never come.
Barcelona was supposed to be crippled by traffic and corruption; Athens' unready state of readiness in 2004 prefaced Greece's economic meltdown, and Beijing 2008 had to cope with human rights outrage and was supposed to be ruined by appalling pollution. All those Olympics took place, with varying degrees of success.
But this is the first Olympics threatened with a public health scare. The call from doctors to postpone or shift the Olympics was never going to happen. Too much money involved, too many impossible logistics and the loudest cries would have come from those the medicos were trying to protect - the athletes, who would have seen it as destruction of their Olympic dream.
Morally, however, the doctors are right. If there is one case of microcephaly which can be attributed to the Olympics, ask the parents - see whether they think postponement/moving the Games might have benefited their child born with a small head and incomplete brain development.
Have a think about Annamay Pierse, the former Canadian swimmer and breaststroke world record holder who contracted dengue fever at the 2010 Commonwealth Games in Delhi. It ruined her career, physically, then mentally. She became depressed and missed selection for London 2012, ending her swimming life.
Yet she, too, insists she'd be going to Rio - Zika or no Zika. "If you talk to some of the people who lost out because the Games were boycotted in 1980, some of them have never gotten over that," she said. "For so many of those athletes, that is the dream ... if someone had said before Beijing, 'I think you should boycott,' there's no way I would have."
The Olympics don't leave hosts with lasting economic benefits, in spite of spin suggesting otherwise.
They don't solve problems. Beijing's air quality was artificially managed during the Games but, on bad days, you could still feel the bad air in the back of your throat.
Eight years later, guess what? Beijing, assailed by the worst pollution in yonks, was forced to issue a red alert. The Olympics might mask a problem but there is little evidence they ever fix one.
So what to do about Rio? Nothing. There's nothing we can do. It's too big, the problems are too big and we'll think about it once the action starts, when a yachtie falls into the poo-infested sea.
And there's the rub. The ones at risk are the athletes (the locals are in danger with or without the Olympics) and they're the ones who want to be there. So maybe it's time the IOC started allocating the Games to places which might not attract the adjective "cursed".
