From a company's perspective you can't assume it's one employee. After all that was just one customers experince. Good businesses, like Starbucks, know this and recognize that corporate culture sometimes needs a reset and they closed down yesterday to do just that. The number of cases like this on Southwest in the last year suggest that they may need a cultural reset too.
I started flying Southwest when I was living in Texas in the early 1980s. There was a charming humorous culture then that they've had to lose a bit of in recent years as they're in much more multicultural markets like California Chicago and the northeast. It's a lot easier to offend with the lame old jokes that I loved. But losing bad jokes to prevent personal offense is a fair trade.
As they stretch their wings more to South and central America they'll need to have a resiliant easy-going corporate culture that can deftly handle an increasingly diverse market with charm. They'd be wise to use this incident and others as a wake up call to re-train their employees to leave any of the biases they may have at home when they go to work. It's not enough to hire a diverse workforce and assume that's enough; they have to be vigilent to protect us from one another. They don't have time for fools like that gate agent.
