I do not feel that Southwest Airlines responded appropriately to Mr. Smith's situation. While there is absolutely no dispute that he is fat, overweight, obese, or unfit, depending on which media outlet is reporting about him and his unfortunate flight, but he was treated unfairly.
Over the past few years, the decision to make passengers purchase an extra ticket if overweight has received much controversy.
The article only makes those with little knowledge of the situation aware that Mr. Smith had an incident on a commercial flight in the past week, and that he was outraged. I have seen much more angry articles, but not his Twitter tweets.

From a P.R. standpoint, I feel that Southwest is doing the right thing. It appears in not just this post, but others as well, that they ARE listening, and are supremely apologetic. Apologetic to the point of sincerity. Also, after consideration of the events, Smith feels slighted, or has made a public statement claiming to feel slighted, on a personal level-from an employees personal feelings towards him. Something that the airline has no control over.

This situation could be saved, if Southwest and Kevin Smith reach an under the table agreement, if Smith agrees to stop bashing Southwest, and the mistake is chalked up to the personally feelings of the employee.

There is a lot of room in this scenario for both parties to save face.