I don't think anyone disagrees that it's the airline's responsibility to provide upkeep for their planes. That is something paramount.
What has to be questioned, is that if what SWA says is true and the FAA did indeed approve their continued use, why the FAA would slap a $10.2million fine on SWA for something that it knowingly approved?
It's like asking your mother if you can get a cookie out of the cookie jar, and your mother says yes, but when she sees you with the cookie, she punishes you or yells at you for having a cookie so close to dinner time.
It's definitely a WTF moment, ya know?