Because you listed one of the reasons you didn't go with NS was the dude with the anti-religious shirt...
Read what I wrote. When you are representing your company, I feel that was inappropriate. If I saw the NS rep at a bar one night wearing the same shirt, I wouldn't think twice about. But when you are doing your job representing your company, everything you do, say and wear is a direct reflection on the company. What you do on your own time is up to you.
If I was in the Army, on the job while working wearing a shirt like that, the Army wouldn't put up with it cause of the image it would bring to the army. But if the Army guy was wearing that shirt off duty at a bar---who cares?