You can make the argument at a lot of places, but Brazil is a democracy. They voted for the candidates who pitched the idea of hosting the Olympics, and it had a mass of popular support.
If the IOC runs out of countries willing to host it, then perhaps the host cities will be able to temper how much they want to spend on it. The Olympics don't have to be so elaborate.
I did not down vote this or the other comment, but I disagree that Brazil is a democracy. It's at best a polyarchy, and is probably just an oligarchy. The voting component is a veneer of democracy to make enough of the citizenry seem essentially complicit with the bad ideas of the leaders.
The IOC won't run out of countries who want to host it so long as countries with rampant corruption exist. The timeline of the Olympics is a corrupt developers wet dream.
If the IOC runs out of countries willing to host it, then perhaps the host cities will be able to temper how much they want to spend on it. The Olympics don't have to be so elaborate.