In the lawsuit, Sims claimed that two female co-workers became openly hostile toward her during a work break after she showed them a business card that identified her as an official with American Atheists. The two women, both Baptists, complained to management and were granted a request to move away from Sims. Two days later, Sims said she found a picture of Jesus on her computer. Sims complained, but supervisor Russell Rogers dismissed her on grounds that she was a disturbance, the lawsuit charged.
I'm not sure why she revealed that she was an atheist, but that was probably a mistake - which is unfortunate, because people shouldn't have to hide who they are simply to maintain a peaceful working environment. Being "in your face" about atheism (or anything else for that matter) wouldn't be appropriate, but a person should be able to casually reveal such things if the relevant context arises. Incidents like this demonstrate just how dangerous such revelations can be.
Who did these people think they were? They had no right to evangelize to a co-worker like that. They have to assume that wherever they work, they will encounter people with different social, political, and religious views. If they can't get along with such diversity, they should simply stay home and shout at people they see or hear the radio and TV.