So, it was trivial, as in "no long lasting effects from his bad behavior nor any crimes committed."
In what way would ending his employment be a punishment that fits the crime? If WDW felt that his behavior warranted it, they could have escorted him from the part and/or banished him. This is a punishment that would fit the crime.
However, causing him to lose his job over this is not a punishment that fits the crime. He wasn't acting as an employee when he did these actions. His bad behavior was not committed in service to his job. Suggesting that he should lose his job is simply retaliation on your part. You don't like his behavior and now you want to make sure he suffers (and suffers much longer than the cast member that had to endure his tirade).
Ultimately, this is just about control. You want to make him an example rather than assure that the "punishment," if needed, fits the crime.
My main issue is the whipping out the phone to hopefully blast them on social media. This is common all over Reddit and it needs to stop, and it should never happen to employees who are just doing their job. Everyone's looking for the next viral "public freakout" video. Thankfully he didn't actually identify the Cast Member in this instance.