Well, here's my two cents on this particular issue:
It's kinda like some people can view a naked human body with little or no reaction while others can't help but blush, get giggly, get sick or can't view it in other people's company. Such religious openness can only bother you if you allow it.
Just last week on the Metro, a man got into the same car as I, said "Good Morning." to everyone in earshot, opened up a hymn book and sang the first two verses of "Jesus Loves Me". After singing, he said, "Have a blessed day." and got off at the next stop. I was standing less than a foot from this man. I also smiled at him and told him "Good Morning" before he left the Metro.
I know some people might have felt uncomfortable about this, some people might have felt "preached to". You don't feel uncomfortable until you feel agitated or threatened on some level. This guy (I'll call him the Singer) had his religion out for all to see but he was not witnessing or preaching in any sort of way. And I encourage people like that. People like the Singer should not be abused, verbally, mentally or physically. Frankly, I think we need more of them. If what the Singer did bothered anyone, then it's not his problem. Nothing he did was threatening in any sort of social manner, unless the listener personally decided it was a threat. Now if the Singer had been shouting at someone, being abusive in the first place, then he would have been a threat and wide open for a counterstrike.
Anyway, my point is the discomfort one feels when encountering another religion is as personal as the joy another feels about a religion, deity or what-have-you. How you react to someone's expression is primarily up to you. There is a difference between affirming your religion and beliefs to someone and forcing them on someone. In a country with religious freedom (this is becoming increasingly questionable), there are basically two choices:
1) To learn to ignore, live-and-let-live or tolerate all the brands of religion one might encounter. One could also learn about these different religions to see past their differences. It might make them more familiar and thus less threatening. OR...
2) Live with being disturbed, bothered or annoyed at every other turn and react expectedly. I'm sure there are some people who would just prefer this choice just for an excuse to agonize people. Humans love that stuff.