I am not an American customer, and not likely to become one. I fly 40-50k miles a year, and have not always been happy with my airline of choice.
I read this piece (http://www.rhrealitycheck.org/article/2012/05/22/american-airlines-rejects-female-passenger-because-political-pro-choice-t-shirt-i) with concern and a little disdain. I can certainly appreciate that American does not wish to allow offensive behavior or messages to be broadcast on the airlines, but this was not a case of that. This was a case of your employees taking matters into their own hands and unnecessarily abusing someone who has a different believe.
Despite what you promote on this site (http://www.aa.com/i18n/aboutUs/diversityInclusion/diversityStatement.jsp), you are not acting in a respectful or tolerant manner.