I would argue that if people self identify as a member of a group, it's not unjustified to have expectations regarding those people
Distrust, for christians, esp. The fundy variety, is a concept for their convenience.
Speaking of TRUST and predjudice...........
Trust is an interesting issue to address that I find quite intriguing. It's an issue that is subject to biases and can be influenced by ignorance and misinfo. I've always wondered what would be the best way to approach not only whether or not you will trust someone that you do not know, but also the extent to which you initially do NOT distrust them.
For me and I'm sure many others who are honest with themselves will agree, it has always been easy to give more trust to a person that you have some commonality with. Having something in common is very disarming and allows for easier communication in my experience. Having been a person that has interviewed others in the past another quality that has influenced my initial trust trust level has been the confidence projected by an individual.
As it relates to interviewing or getting a job, I tell any prospect that the more a person can be defined and classified, whether that classification is based on religion or something else, the more data employers THINK they have to make judgments about what can be expected from a person. If a person is a declared atheist and the employer knows nothing else about them, what their values are, etc., the employer must probe more to get an idea about them than say a person of faith because faith gives me something to go on as I try to make a quick judgment about a stranger. Employers typically do not want to spend the time probing, (though doing so could prove beneficial to the ER in the long run). I guess that is why many find it valuable to list all the organizations and groups they are a part of on their resumes. Doing so helps the potential employer get an idea about what type of person you may be and what types of values you may have.
Where faith creeps in for me as it relates to my perception of how much I should trust a person has more to do with whether or not a person has convictions they subject themselves and their behaviors to. We know of many specific convictions, or at least we believe that many believers have certain guidelines they are compelled to abide by. For those without any declared faith, the waters are more muddy as we have no grounds to use to come up with our (often faulty, but often employed) preconceptions.