Irritating quirks . . .
Some countries are "owned" by their bureaucracies.
One reason NOT to go to SA.
But they don't care; after all they are a rich, industrialized country, they don't need discretionary visitors.
South Africa has a problem with our visitors seeming to like our country so much that they forget to want to leave. The one page requirement is their should you need to apply for a visa that they can insert the visa on your passport and they require a blank page for that. We allow most visitors 90 days visa free but should you want to extend you have the required page to do so. South Africa is not a rich country we a developing country like Brazil.