This incident will probably force me to buy another car and I will never buy a car with this kind of gas cap opener again!
Calm down, ease up on the hyperbole and spend the energy on finding a solution. A gas cap door freezing up is not a reason to dump a good car and spend $30K on another, although I understand that you are frustrated.
Further, MANY cars have gas cap locks of this type that are actuated by the door locks. Gas theft has made it a common feature...so if you'll never buy another car with one, your selection is about to become very limited.
I suggest to those who are dealing with this problem to use some spray silicone or liquid graphite on the actuator pin, NOT any kind of oil or grease. Oil and grease attract and retain dust and grit, and eventually the buildup of grit creates an abrasive slurry. This makes the problem worse, not better. Lubricants such as silicone and graphite are much less prone to attract and hold grit and dust, and are therefore preferable.
And WD-40 is not a lubricant, it's a water-displacing solution. Although it may flush out some accumulated material and act as a very temporary lubricant, for ongoing lubrication silicone or graphite will work much better.