You can still download a game you purchased, even if it is gone from the store. You just can't buy it anymore if you didn't already. The tweet is worded a little confusingly. You shouldn't need to download it if you bought it.
I've downloaded games that were gone from the store a couple of times.
I actually just purchased the Disney Afternoon Collection since it was on sale. Pretty sure that includes the original version of the game so I'll probably just stick with that.