Thiel's concept of the definite optimist. It is not enough to be an optimist. You need to think about the future in a definite manner. That does not mean that everything you plan will work out. It is easier said than done. But being a definite optimist is the first step to be in control of your destiny.
Developing optimism and resiliency isn't about feigning a facsimile of terminal perkiness and blind optimism. It's quite the opposite. It's having the courage to see and meet life exactly as it is. It's all about choosing to learn how to respond to each adversity with confidence, hope and renewed vigor.
What can we do against an enemy with no moral compass? I'm afraid we must expose them as the murderers they are. And how can we do that? Short term, we can unite in our opposition to their behavior, we can punish the people who fund them, and we can rise in defense of those whom they most brutally oppress.