It's a complex situation and one that is specific to the individual.
I guess I should clarify, I don't personally find it hard to trust, just that I need to see people earn it as trusting a person blindly with no evidence that they deserve it seems rather bonkers to me.
It's worked for 52 years so far, and whilst I've placed trust in the wrong places previously, and also in the right places, I still seek evidence that trust is deserved before I give it.
Blind trust doesn't seem prudent no matter the amount of faith a person has in humanity. We all know there's people out there who don't deserve trust, and that's there's other people who do, it's situational, and actions will determine who is who.
A parent sending their 10 year old to the playground by themselves trusting in their faith in humanity may not work out so well these days. Back where and when I was 10 it was considered normal. That situation may also be location specific. Just an example of how blind trust may be misplaced.
Times change, and people need to change with them because people force those changes societal changes.
Thanks for your comment.