I think because it is always "easier" to make yourself less vulnerable. When you choose to trust someone, you make yourself vulnerable; hence, the fear. When trust is earned, the fear of vulnerability should eventually diminish.
I think most fear derives from ghosts of our past. We may seek to be free from them, but experience makes us what we are. Besides, fear, if controlled, is a healthy emotion.
On the other hand, being skeptical and jaded is not. Your question itself, shows me you are not jaded.
Trust like Respect has to be earned. Trust should only be given to someone who has proven to you they lead their life with honesty and integrity. If you trust someone you will not have "fear".
If you do have fear it may be that you don't trust (yourself) enough to choose trustworthy people. Only introspective thinking, time, experience, and wisdom can remedy that.
Trust has to be earned. If it is earned then there won't be fear. But you have to give someone a chance for them to earn your trust, and that part is scary because it means opening yourself up to the possiblility of being hurt.
But giving someone a chance is not the same as really trusting them.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.