Bigotry, in my opinion is caused by several preconceived notions, or to put it simply, ignorance.
The article states " While reasons behind antagonism toward atheists have not been fully explored the study is among the first explorations of the social psychological processes underlying anti-atheist sentiments." and then grasps on to this issue of trust and rockets it to the top of the list of things Atheists need to worry about. Lack trust is a result of bigotry ad the bigotry is caused by ignorance.
IGNORANCE: the state or fact of being ignorant : lack of knowledge, education, or awareness
Most people don't know any Atheists or at least they don't think they do. If someone is a bigot against gays, it's usually because they don't know any gay people. As homosexuals have become more open, the acceptance of them has grown. When your kids teacher is doing a great job motivating the children and half way into the school year you find out he is gay it's going to be more difficult to say gays can't teach. Of course there are going to be some who would say that still but you can't fix stupid.
THAT is the reason we need to be vocal and we need others to at least be open about their lack of beliefs in god or more importantly, in the failure of religion to stand up to reasonable questions about it's validity. While I do not believe in a god or gods I feel it is more important that we focus on how silly religion is. It's a much more simple argument to prove. Once you get people to question the beliefs they hold just because their mother and father said so or because it makes them feel good by putting it to a very basic examination then they will look to other belief systems. Since all belief systems are basically built from the same type of shaky foundation and stem from fantastic stories you end up with an Agnostic which eventually (from my experience) will lead a person to Atheism. This depends on the person caring enough to go that far, many people simply don't care enough about religion and I don't think those people are ones we need to worry about forcing religion into our personal lives or government.
When we proclaim "There is no god!" we take something that people feel gives their lives meaning and try to crush it. We need them to think about the meaning being a different one than they currently believe in. Once you get people thinking they won't stop....I think.