I see the "False optimism" as people who trick themselves into believing a false truth, a fantasy, a paradise. I see these people as people who will then either be completely stressed out on the smallest problem or will end up begging for money.
I see "realistic optimism" as enthusiasm, which is the type of people that make themselves, and others feel better and do better, and look forward to a bright future. I see this type of people as people that will be successful in the future.