This is not the same scenario ! If you put a hold on an item at Target that was perishable (or the system allowed you to do
it without any consequences) AND you did not buy it, then Target could not resell it and it is a loss. AA's product is perishable
as well so AA probably did lose money on the tickets that you blocked with your expired CC. AA should not have in the first
place allowed you to hold the ticket beyond the normal hold window if they did not realize the revenue.
That is on AA and its IT !

On the other hand I am not sure how many such tickets you had on hold and if you continued to do it over a long time
knowingly, then you were gaming the system. That understandably upsets lot of honest people although as I pointed out, many
here buy mistake fares, enjoy first class at economy prices and write trip reports...so I do not see any difference between that
and your behavior !!