Whether you or anyone else likes it, the FAA calls the shots about the way aviation is supposed to work in the US. I am sure your logic makes plenty of sense, but the FAA does not allow airlines to rewrite the rules or alter them based on their logic.
No, the FAA is not piling on AA because they do their work in-house. If that was the case, then DL with the next lowest percentage of maintenance outsourced should get some proportional fine.
While there needs to be better oversight of foreign repair stations, the FAA does inspect planes in the US. As long as those planes come back to the US after being serviced overseas, the FAA can and will find what is at fault - and the operating airline is responsible for ensuring they meet FAA requirements, regardless of whether repairs are done at DFW or on Mars.