Cynically optimistic person is somebody who acknowledges the fact that humanity is crap but also believes in its capacity to do good.

“乐观的愤世嫉俗者”指那些承认人性黑暗但同时也相信人能行善的人。

Example:

If you're that person who wants to cut the next jerk who cuts you in line, but also has genuine faith in humanity, you're cynically optimistic.

如果你看到有人在你前面插队但却视而不见，但同时又对人性保持信仰，那么你就是个乐观的愤世嫉俗者。